The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is pro...The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η~4-diene (cis-trans-)and η~3-allyl (syn-anti-).展开更多
A new method of producing tungstic acid with a yield over 98% at room temperature and low acidity is advanced and referred to as Complcx -Homogeneous Precipitation Method. If combined with the treatment of activated c...A new method of producing tungstic acid with a yield over 98% at room temperature and low acidity is advanced and referred to as Complcx -Homogeneous Precipitation Method. If combined with the treatment of activated charcoal in recovering the remnant tungsten left in the filter liquor, a perfect closed technological process can be obtained. The key to this method is to prevent the formation of pseudo-metatungstatc during scdium rungstate being acidified directly with the aid of the complexing-protecting agent H2O2, The perexo-mtermediate, which was prepated and identified as dipcroxytetratnngstate by IR and Raman analysis by comparison with diperorytetramolybdate, can be decomposed by SO2 tapidly and quantitatively. The tungstic acid precipitate can be filtered and washed easily. The related mechanisin is studied.展开更多
Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome t...Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.展开更多
Feature initialization is an important issue in the monocular simultaneous locahzation ana mapping （SLAM） literature as the feature depth can not be obtained at one observation. In this paper, we present a new featu...Feature initialization is an important issue in the monocular simultaneous locahzation ana mapping （SLAM） literature as the feature depth can not be obtained at one observation. In this paper, we present a new feature initialization method named modified homogeneous parameterization （MHP）, which allows undelayed initialization with scale invariant representation of point features located at various depths. The linearization error of the measurement equation is quantified using a depth estimation model and the feature initialization process is described. In order to verify the performance of the proposed method, the simulation is carried out. Results show that with the proposed method, the SLAM algorithm can achieve better consistency as compared with the existing inverse depth parameterization （IDP） method.展开更多
This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional（3D） range-intensity correlation laser imaging. Firstly, features and feature pairs of gate i...This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional（3D） range-intensity correlation laser imaging. Firstly, features and feature pairs of gate images are obtained by speeded-up robust figures and bi-directional feature matching methods. The original mean value of the feature-pair coordinate differences is calculated. Comparing the coordinate differences with the original mean value, the wrong feature pairs are removed, and then an optimized mean value is updated. The final feature-pair coordinates are re-registered based on the updated mean value. Thus, an accurate transformation is established to rectify motion gate images for 3D reconstruction. In the experiment, a 3D image of a tower at 780 m is successfully captured by our laser gated imaging system on a pan-tilt device.展开更多
基金The Project is supported by "Laboratory of Physics & Chemistry, Academia Sinica" and "National Natural Science Foundation of China"
文摘The reaction mechanisms of diene polymerization with homogeneous rare earth catalyst are studied by means of the spectra of ~1H-NMR, one-and two-dimensions ^(13)C-NMR. Based on the data of above NMR spectra, it is proposed that the polymerization reaction proceeds according to the following mechanism: η~4-diene (cis-trans-)and η~3-allyl (syn-anti-).
文摘A new method of producing tungstic acid with a yield over 98% at room temperature and low acidity is advanced and referred to as Complcx -Homogeneous Precipitation Method. If combined with the treatment of activated charcoal in recovering the remnant tungsten left in the filter liquor, a perfect closed technological process can be obtained. The key to this method is to prevent the formation of pseudo-metatungstatc during scdium rungstate being acidified directly with the aid of the complexing-protecting agent H2O2, The perexo-mtermediate, which was prepated and identified as dipcroxytetratnngstate by IR and Raman analysis by comparison with diperorytetramolybdate, can be decomposed by SO2 tapidly and quantitatively. The tungstic acid precipitate can be filtered and washed easily. The related mechanisin is studied.
基金State Administration of Science,Technology and Industry for the National Defense(No.JSJL2014206B001)。
文摘Light pen coordinate measuring system(LPCMS)is a kind of portable coordinate measuring technique based on vision metrology.In classical LPCMS,the measuring range is limited to the camera’s field of view.To overcome this defect,a new LPCMS is designed in this paper to fulfil whole space coordinate measurement.The camera is installed on a turntable instead of a tripod,so that the camera can rotate to track the movement of the light pen.The new system can be applied to large scale onsite measurement,and therefore it notably extends the application of LPCMS.To guarantee the accuracy of the new system,a method to calibrate the parameters of the tracking turntable is also proposed.Fixing the light pen at a stationary position,and changing the azimuth angles of the turntable’s two shafts,so that the camera can capture the images of the light pen from different view angles.According to the invariant spatial relationship between the camera and the pedestal of the tracking turntable,a system of nonlinear equations can be established to solve the parameters of the turntable.Experimental results show that the whole space coordinate measuring accuracy of the new system can reach 0.25 mm within 10 m.It can be concluded that the newly designed system can significantly expand the measuring range of LPCMS without losing too much accuracy.
文摘Feature initialization is an important issue in the monocular simultaneous locahzation ana mapping （SLAM） literature as the feature depth can not be obtained at one observation. In this paper, we present a new feature initialization method named modified homogeneous parameterization （MHP）, which allows undelayed initialization with scale invariant representation of point features located at various depths. The linearization error of the measurement equation is quantified using a depth estimation model and the feature initialization process is described. In order to verify the performance of the proposed method, the simulation is carried out. Results show that with the proposed method, the SLAM algorithm can achieve better consistency as compared with the existing inverse depth parameterization （IDP） method.
基金supported by the National Key Research and Development Program of China(No.2016YFC0500103)the Youth Innovation Promotion Association CAS(No.2017155)the Scientific Instrument Development Project from Capital Science and Technology Condition Platform(No.Z171100002817002)
文摘This Letter proposes a coordinate difference homogenization matching method to solve motion influence in three-dimensional（3D） range-intensity correlation laser imaging. Firstly, features and feature pairs of gate images are obtained by speeded-up robust figures and bi-directional feature matching methods. The original mean value of the feature-pair coordinate differences is calculated. Comparing the coordinate differences with the original mean value, the wrong feature pairs are removed, and then an optimized mean value is updated. The final feature-pair coordinates are re-registered based on the updated mean value. Thus, an accurate transformation is established to rectify motion gate images for 3D reconstruction. In the experiment, a 3D image of a tower at 780 m is successfully captured by our laser gated imaging system on a pan-tilt device.
