The real in time computerized tomography (CT) testing of the meso damage propagation law of the whole sandstone failure process under triaxial compression has been completed using the newest specified triaxial loading...The real in time computerized tomography (CT) testing of the meso damage propagation law of the whole sandstone failure process under triaxial compression has been completed using the newest specified triaxial loading equipment corresponding to the CT machine. Through the CT scanning, the clear CT images which include from the microcracks compressed stage to growth stage, bifurcation stage, development stage, crack fracture stage,the rock sample failure until to unloading stage in the different stress states were obtained. The CT values, CT images and the other data have been analyzed. Based on the results of the CT testing of meso damage evolution law of rock,the stress threshold value of meso damage of rock is given, and the stress strain complete process curve of rock is divided into some sections. The initial rock damage propagation law is given in this paper.展开更多
Using dipyridamole stress test to evaluate cerebral blood flow reserve in cerebrovascular disease (CVD). Dipyridamole stress tests were performed first, the baseline SPECT images were obtained under similar conditions...Using dipyridamole stress test to evaluate cerebral blood flow reserve in cerebrovascular disease (CVD). Dipyridamole stress tests were performed first, the baseline SPECT images were obtained under similar conditions 2-5 days later. By visual and semiquantitative analysis, the responses of cerebral blood flow to dipyridamole were divided into the following four patterns: A: The dipyridamole SPECT showed an expanded area of hypoperfusion, Asymmetry Index(AI) and Uptake Rate(UR) were all decreased; B: Rest images was normal but new hypoperfused areas appeared on stress test with decreased Al and UR; C: Hypoperfused areas were decreased in size or disappeared after stress test with increased Al and UR; D: No changes showed in cerebral perfusion imaging patterns, and in Al and UR between stress and rest studies. Dipyridarnole brain perfusion imaging may be helpful to the diagnosis of CVD, to the decision the therapeutic plan, and to predicting the therapeutic effect.展开更多
Mutual information has currently been one of the most intensivelyresearched measures. It has been proven to be accurate and effective registrationmeasure. Despite the general promising results, mutual information some...Mutual information has currently been one of the most intensivelyresearched measures. It has been proven to be accurate and effective registrationmeasure. Despite the general promising results, mutual information sometimes mightlead to misregistration because of neglecting spatial information and treating intensityvariations with undue sensitivity. In this paper, an extension of mutual informationframework was proposed in which higher-order spatial information regarding imagestructures was incorporated into the registration processing of PET and MR. Thesecond-order estimate of mutual information algorithm was applied to the registrationof seven patients. Evaluation from Vanderbilt University and our visual inspectionshowed that sub-voxel accuracy and robust results were achieved in all cases withsecond-order mutual information as the similarity measure and with Powell's multi-dimensional direction set method as optimization strategy.展开更多
It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant t...It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant to temperature or density. In this paper, a new multidirectional holographic interferometric system is built, and two kinds of image reconstruction algorithms are introduced and an automatic image processing system of interferogram is designed. A three dimentsional asymmetric gas flow field above a combustor is expertmentally investigated with holographic interferometry. The reconstructed temperatures are similar to those measured with a thermocouple.展开更多
Electrical capacitance tomography(ECT) was applied in measuring solids distribution in square circulating fluidized beds. The fluidization conditions varied from bubbling fluidized bed to circulating fluidized bed. In...Electrical capacitance tomography(ECT) was applied in measuring solids distribution in square circulating fluidized beds. The fluidization conditions varied from bubbling fluidized bed to circulating fluidized bed. In the whole range of fluidization conditions, ECT was able to instantaneously provide the solids concentration and voids distributions in the fluidized beds. According to the acquired data from ECT and reconstructed image, different fluidization regimes can also be identified.展开更多
基金FundofStateKeyLaboratoryofFrozenSoilEngineeringofChina !(No 980 2 No 2 0 0 3 )
文摘The real in time computerized tomography (CT) testing of the meso damage propagation law of the whole sandstone failure process under triaxial compression has been completed using the newest specified triaxial loading equipment corresponding to the CT machine. Through the CT scanning, the clear CT images which include from the microcracks compressed stage to growth stage, bifurcation stage, development stage, crack fracture stage,the rock sample failure until to unloading stage in the different stress states were obtained. The CT values, CT images and the other data have been analyzed. Based on the results of the CT testing of meso damage evolution law of rock,the stress threshold value of meso damage of rock is given, and the stress strain complete process curve of rock is divided into some sections. The initial rock damage propagation law is given in this paper.
文摘Using dipyridamole stress test to evaluate cerebral blood flow reserve in cerebrovascular disease (CVD). Dipyridamole stress tests were performed first, the baseline SPECT images were obtained under similar conditions 2-5 days later. By visual and semiquantitative analysis, the responses of cerebral blood flow to dipyridamole were divided into the following four patterns: A: The dipyridamole SPECT showed an expanded area of hypoperfusion, Asymmetry Index(AI) and Uptake Rate(UR) were all decreased; B: Rest images was normal but new hypoperfused areas appeared on stress test with decreased Al and UR; C: Hypoperfused areas were decreased in size or disappeared after stress test with increased Al and UR; D: No changes showed in cerebral perfusion imaging patterns, and in Al and UR between stress and rest studies. Dipyridarnole brain perfusion imaging may be helpful to the diagnosis of CVD, to the decision the therapeutic plan, and to predicting the therapeutic effect.
基金The images and the standard transformation were provided as part of the project,"Retrospective Im-age Registration Evaluation"(National Institutes of Health,1 R01 CA89323),the principal investigator,J.Michael Fitzpatrick,Vanderbilt Universi
文摘Mutual information has currently been one of the most intensivelyresearched measures. It has been proven to be accurate and effective registrationmeasure. Despite the general promising results, mutual information sometimes mightlead to misregistration because of neglecting spatial information and treating intensityvariations with undue sensitivity. In this paper, an extension of mutual informationframework was proposed in which higher-order spatial information regarding imagestructures was incorporated into the registration processing of PET and MR. Thesecond-order estimate of mutual information algorithm was applied to the registrationof seven patients. Evaluation from Vanderbilt University and our visual inspectionshowed that sub-voxel accuracy and robust results were achieved in all cases withsecond-order mutual information as the similarity measure and with Powell's multi-dimensional direction set method as optimization strategy.
文摘It is well known that optical tomography can accurately and quantitatively reconstruct the refractive index field of a transparent medium and display the three dimensional image of other physical quantities relevant to temperature or density. In this paper, a new multidirectional holographic interferometric system is built, and two kinds of image reconstruction algorithms are introduced and an automatic image processing system of interferogram is designed. A three dimentsional asymmetric gas flow field above a combustor is expertmentally investigated with holographic interferometry. The reconstructed temperatures are similar to those measured with a thermocouple.
文摘Electrical capacitance tomography(ECT) was applied in measuring solids distribution in square circulating fluidized beds. The fluidization conditions varied from bubbling fluidized bed to circulating fluidized bed. In the whole range of fluidization conditions, ECT was able to instantaneously provide the solids concentration and voids distributions in the fluidized beds. According to the acquired data from ECT and reconstructed image, different fluidization regimes can also be identified.
