Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the so...Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the solid Earth tide, as signals, from static relative gravimetric data assuming that the components contained in the relative gravimetric data are uncorrelated. Static relative gravity observations from Aug. 15 to Aug. 23, 2014 are used as statistical variables to separate the signal and noise with PCA to obtain desired signals. The results of the linear drift extracted by PCA are consistent with those calculated by the least squares linear fitting, and the differences only reach to 10-2μGal/day order of magnitude. Furthermore, PCA is used to estimate the solid Earth tide from the relative gravimetric data corrected by the zero drift. The statistical results are consistent with the results derived from the solid Earth tide correction provided by the internal software of the CG-5 gravimeter （SCINTREX Limited Ontario Canada）. The statistical results of the differences between the two methods are both less than 8 ,Gal, and the RMSs for 9 days are all less than 5 μGal.展开更多
This paper investigates the magnetic field component impact on cathode spots motion trajectory and the mechanism of periodic contraction.Electromagnetic coils and permanent magnets were installed at the different side...This paper investigates the magnetic field component impact on cathode spots motion trajectory and the mechanism of periodic contraction.Electromagnetic coils and permanent magnets were installed at the different sides of cathode surface,the photographs of cathode spots motion trajectory were captured by a camera.Increasing the number of magnets and decreasing the distance between magnets and cathode both lead to enhancing cathode spots motion velocity.Radii of cathode spots trajectory decrease gradually with the increasing of electromagnetic coil＇s current,from 40 mm at 0 A to 10 mm at 2.7 A.Parallel magnetic field component intensity influence the speed of cathode spots rotate motion,and perpendicular magnetic field component drives spots drift in the radial direction.Cathode spot＇s radial drift is controlled by changing the location of the ‘zero line＇ where perpendicular magnetic component shifts direction and the radius of cathode spots trajectory almost equal to ‘zero line＇.展开更多
Intracranial pressure(ICP)is one of the most important indexes in neurosurgery.It is essential for doctors to determine the numeric value and changes of ICP,whether before or after an operation.Although external ventr...Intracranial pressure(ICP)is one of the most important indexes in neurosurgery.It is essential for doctors to determine the numeric value and changes of ICP,whether before or after an operation.Although external ventricular drainage(EVD)is the gold standard for monitoring ICP,more and more novel monitoring methods are being applied clinically.Invasive wired ICP monitoring is still the most commonly used in practice.Meanwhile,with the rise and development of various novel technologies,non-invasive types and invasive wireless types are gradually being used clinically or in the testing phase,as a complimentary approach of ICP management.By choosing appropriate monitoring methods,clinical neurosurgeons are able to obtain ICP values safely and effectively under particular conditions.This article introduces diverse monitoring methods and compares the advantages and disadvantages of different monitoring methods.Moreover,this review may enable clinical neurosurgeons to have a broader view of ICP monitoring.展开更多
A wireless passive pressure sensor equivalent to inductive-capacitive （LC） resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization process...A wireless passive pressure sensor equivalent to inductive-capacitive （LC） resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization processes. Cylindrical copper spiral reader antenna and insulation layer are designed to realize the wireless measurement for the sensor in high temperature environment. The high temperature performance of the sensor is analyzed and discussed by studying the phase-frequency and amplitude-frequency characteristics of reader antenna. The average frequency change of sensor is 0.68 kHz/℃ when the temperature changes from 27℃ to 700℃ and the relative change of twice measurements is 2.12%, with high characteristic of repeatability. The study of temperature-drift characteristic of pressure sensor in high temperature environment lays a good basis for the temperature compensation methods and insures the pressure signal readout accurately.展开更多
基金supported by the National Natural Science Foundation of China(41374009)the Public Benefit Scientific Research Project of China(201412001)+1 种基金the Shandong Natural Science Foundation of China(ZR2013DM009)the SDUST Research Fund(2014TDJH101)
文摘Zero drift and solid Earth tide corrections to static relative gravirnetric data cannot be ignored. In this paper, a new principal component analysis （PCA） algorithm is presented to extract the zero drift and the solid Earth tide, as signals, from static relative gravimetric data assuming that the components contained in the relative gravimetric data are uncorrelated. Static relative gravity observations from Aug. 15 to Aug. 23, 2014 are used as statistical variables to separate the signal and noise with PCA to obtain desired signals. The results of the linear drift extracted by PCA are consistent with those calculated by the least squares linear fitting, and the differences only reach to 10-2μGal/day order of magnitude. Furthermore, PCA is used to estimate the solid Earth tide from the relative gravimetric data corrected by the zero drift. The statistical results are consistent with the results derived from the solid Earth tide correction provided by the internal software of the CG-5 gravimeter （SCINTREX Limited Ontario Canada）. The statistical results of the differences between the two methods are both less than 8 ,Gal, and the RMSs for 9 days are all less than 5 μGal.
文摘This paper investigates the magnetic field component impact on cathode spots motion trajectory and the mechanism of periodic contraction.Electromagnetic coils and permanent magnets were installed at the different sides of cathode surface,the photographs of cathode spots motion trajectory were captured by a camera.Increasing the number of magnets and decreasing the distance between magnets and cathode both lead to enhancing cathode spots motion velocity.Radii of cathode spots trajectory decrease gradually with the increasing of electromagnetic coil＇s current,from 40 mm at 0 A to 10 mm at 2.7 A.Parallel magnetic field component intensity influence the speed of cathode spots rotate motion,and perpendicular magnetic field component drives spots drift in the radial direction.Cathode spot＇s radial drift is controlled by changing the location of the ‘zero line＇ where perpendicular magnetic component shifts direction and the radius of cathode spots trajectory almost equal to ‘zero line＇.
文摘Intracranial pressure(ICP)is one of the most important indexes in neurosurgery.It is essential for doctors to determine the numeric value and changes of ICP,whether before or after an operation.Although external ventricular drainage(EVD)is the gold standard for monitoring ICP,more and more novel monitoring methods are being applied clinically.Invasive wired ICP monitoring is still the most commonly used in practice.Meanwhile,with the rise and development of various novel technologies,non-invasive types and invasive wireless types are gradually being used clinically or in the testing phase,as a complimentary approach of ICP management.By choosing appropriate monitoring methods,clinical neurosurgeons are able to obtain ICP values safely and effectively under particular conditions.This article introduces diverse monitoring methods and compares the advantages and disadvantages of different monitoring methods.Moreover,this review may enable clinical neurosurgeons to have a broader view of ICP monitoring.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 61471324） and the Outstanding Young Talents Support Plan of Shanxi province.
文摘A wireless passive pressure sensor equivalent to inductive-capacitive （LC） resonance circuit and based on alumina ceramic is fabricated by using high temperature sintering ceramic and post-fire metallization processes. Cylindrical copper spiral reader antenna and insulation layer are designed to realize the wireless measurement for the sensor in high temperature environment. The high temperature performance of the sensor is analyzed and discussed by studying the phase-frequency and amplitude-frequency characteristics of reader antenna. The average frequency change of sensor is 0.68 kHz/℃ when the temperature changes from 27℃ to 700℃ and the relative change of twice measurements is 2.12%, with high characteristic of repeatability. The study of temperature-drift characteristic of pressure sensor in high temperature environment lays a good basis for the temperature compensation methods and insures the pressure signal readout accurately.
