A new moored microstructure recorder(MMR) is designed, developed, tested, and evaluated. The MMR directly measures the high-frequency shear of velocity fl uctuations, with which we can estimate the dissipation rate of...A new moored microstructure recorder(MMR) is designed, developed, tested, and evaluated. The MMR directly measures the high-frequency shear of velocity fl uctuations, with which we can estimate the dissipation rate of turbulent kinetic energy. We summarize and discuss methods for estimating the turbulent kinetic energy dissipation rate. Instrument body vibrations contaminate the shear signal in an ocean fi eld experiment, and a compensating correction successfully removes this contamination. In both tank test and ocean fi eld experiment, the dissipation rate measured with the MMR agreed well with that measured using other instruments.展开更多
Aiming at evaluating the stability of a rock mass near a fault,a microseismic(MS) monitoring system was established in Hongtoushan copper mine.The distribution of displacement and log(/),the relationship between MS ac...Aiming at evaluating the stability of a rock mass near a fault,a microseismic(MS) monitoring system was established in Hongtoushan copper mine.The distribution of displacement and log(/),the relationship between MS activity and the exploitation process,and the stability of the rock mass controlled by a fault were studied.The results obtained from microseismic data showed that MS events were mainly concentrated al the footwall of the fault.When the distance to the fault exceeded 20 m,the rock mass reached a relatively stable state.MS activity is closely related to the mining process.Under the strong disturbance from blasting,the initiation and propagation of cracks is much faster.MS activity belongs in the category of aftershocks after large scale excavation.The displacement and log(C/) obtained from MS events can reflect the difference in physical and mechanical behavior of different areas within the rock mass,which is useful in judging the integrity and degradation of the rock mass.展开更多
Reomtly, Coordinate bieasuring Machines （CMMs） are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to t...Reomtly, Coordinate bieasuring Machines （CMMs） are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to the Expression of Uncertainty in Measta- meat （GUM）, all measurement results must have a stated uncertainty associated the titan. However, no CMMs give the uncertainty value of the roundness, because no suitable measrement uncertainty calculation procedure exists. In the case of roundness raeasurement in coordinate metrology, this paper suggests the algorithms for the calculation of the measurement uncertainty of the roudness deviation based on the two mainly used association criteria, LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculatiion can be done by autnatic differentiation, in order to avoid introducing additional emars by the traditional difference quotient approxima- tions. The proposed methods are exact and need input data only as the nrasured coordinates of the data points and their associated un- certainties.展开更多
A micro turbo-expander capable of high working speed was specially manufactured for use in an organic Rankine cycle (ORC).A series of tests were executed to examine the performance of the machine.In the experiment,the...A micro turbo-expander capable of high working speed was specially manufactured for use in an organic Rankine cycle (ORC).A series of tests were executed to examine the performance of the machine.In the experiment,the machine was tested under different inlet pressure conditions (0.2-0.5 MPa).Data such as the compressed air pressure,temperatures of the inlet and the outlet,rotational speed,and electric power generation were analyzed to discover underlying relationships.During the test,the rotational speed of the machine reached as high as 54 000 r/min,the peak value of the temperature drop between the inlet and the outlet reached 42 ℃,the maximum electric power generated by the motor-generator attached to the machine reached 630 W,and the efficiency of the machine reached 0.43.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41006005,40906004,91028008,40890153,41176008,41176010)the National High Technology Research and Development Program of China(863 Program)(No.2008AA09A402)the Program for New Century Excellent Talents in University(No.NCET-10-0764)
文摘A new moored microstructure recorder(MMR) is designed, developed, tested, and evaluated. The MMR directly measures the high-frequency shear of velocity fl uctuations, with which we can estimate the dissipation rate of turbulent kinetic energy. We summarize and discuss methods for estimating the turbulent kinetic energy dissipation rate. Instrument body vibrations contaminate the shear signal in an ocean fi eld experiment, and a compensating correction successfully removes this contamination. In both tank test and ocean fi eld experiment, the dissipation rate measured with the MMR agreed well with that measured using other instruments.
基金financially supported by Projects of the National Key Technology R&D Program of China(Nos.2013BAB02B01 and2013BAB02B03)the National Natural Science Foundation of China(Nos.51274055 and 51204030)+1 种基金the Fundamental Research Funds for the Central University of China(Nos.N130401006,N120801002 and N120701001)the Key Science&Technology Special Project of Third Five-Year Plan of MCC(No.0012012009)
文摘Aiming at evaluating the stability of a rock mass near a fault,a microseismic(MS) monitoring system was established in Hongtoushan copper mine.The distribution of displacement and log(/),the relationship between MS activity and the exploitation process,and the stability of the rock mass controlled by a fault were studied.The results obtained from microseismic data showed that MS events were mainly concentrated al the footwall of the fault.When the distance to the fault exceeded 20 m,the rock mass reached a relatively stable state.MS activity is closely related to the mining process.Under the strong disturbance from blasting,the initiation and propagation of cracks is much faster.MS activity belongs in the category of aftershocks after large scale excavation.The displacement and log(C/) obtained from MS events can reflect the difference in physical and mechanical behavior of different areas within the rock mass,which is useful in judging the integrity and degradation of the rock mass.
基金supported by the National Natural Science Foundation of China(No.50705002,50627501)
文摘Reomtly, Coordinate bieasuring Machines （CMMs） are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to the Expression of Uncertainty in Measta- meat （GUM）, all measurement results must have a stated uncertainty associated the titan. However, no CMMs give the uncertainty value of the roundness, because no suitable measrement uncertainty calculation procedure exists. In the case of roundness raeasurement in coordinate metrology, this paper suggests the algorithms for the calculation of the measurement uncertainty of the roudness deviation based on the two mainly used association criteria, LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculatiion can be done by autnatic differentiation, in order to avoid introducing additional emars by the traditional difference quotient approxima- tions. The proposed methods are exact and need input data only as the nrasured coordinates of the data points and their associated un- certainties.
基金Project (Nos.50974150 and 50708105) supported by the National Natural Science Foundation of China
文摘A micro turbo-expander capable of high working speed was specially manufactured for use in an organic Rankine cycle (ORC).A series of tests were executed to examine the performance of the machine.In the experiment,the machine was tested under different inlet pressure conditions (0.2-0.5 MPa).Data such as the compressed air pressure,temperatures of the inlet and the outlet,rotational speed,and electric power generation were analyzed to discover underlying relationships.During the test,the rotational speed of the machine reached as high as 54 000 r/min,the peak value of the temperature drop between the inlet and the outlet reached 42 ℃,the maximum electric power generated by the motor-generator attached to the machine reached 630 W,and the efficiency of the machine reached 0.43.
