An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo...An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.展开更多
The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation met...The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation methods, a new approach based on the shadow area percentage （SAP） that can be used to quantify surface roughness is proposed in this article. Firstly, by the help of laser scanning technique, the three-dimensional model of the surface of rock discontinuity was established. Secondly, a light source was simulated, and there would be some shadows produced on the model surface. Thirdly, to obtain the value of SAP of each specimen, the shadow detection technique was introduced for use. Fourthly, compared with the result from direct shear testing and based on statistics, an empirical for- mula was found among SAP, normal stress, and shear strength. Data of Yujian （~ River were used as an example, and the following conclusions have been made. （1） In the case of equal normal stress, the peak shear stress is positively proportional to the SAP. （2） The formula for estimating was derived, and the predictions of peak-shear strength made with this equation well agreed with the experimental re- suits obtained in laboratory tests.展开更多
Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyze...Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.展开更多
Fracture surface contour study is one of the important requirements for characterization and evaluation of the microstructure of rocks.Based on the improved cube covering method and the 3D contour digital reconstructi...Fracture surface contour study is one of the important requirements for characterization and evaluation of the microstructure of rocks.Based on the improved cube covering method and the 3D contour digital reconstruction model,this study proposes a quantitative microstructure characterization method combining the roughness evaluation index and the 3D fractal dimension to study the change rule of the fracture surface morphology after blasting.This method was applied and validated in the study of the fracture microstructure of the rock after blasting.The results show that the fracture morphology characteristics of the 3D contour digital reconstruction model have good correlation with the changes of the blasting action.The undulation rate of the three-dimensional surface profile of the rock is more prone to dramatic rise and dramatic fall morphology.In terms of tilting trend,the tilting direction also shows gradual disorder,with the tilting angle increasing correspondingly.All the roughness evaluation indexes of the rock fissure surface after blasting show a linear and gradually increasing trend as the distance to the bursting center increases;the difference between the two-dimensional roughness evaluation indexes and the three-dimensional ones of the same micro-area rock samples also becomes increasingly larger,among which the three-dimensional fissure roughness coefficient JRC and the surface roughness ratio Rs display better correlation.Compared with the linear fitting formula of the power function relationship,the three-dimensional fractal dimension of the postblast fissure surface is fitted with the values of JRC and Rs,which renders higher correlation coefficients,and the degree of linear fitting of JRC to the three-dimensional fractal dimension is higher.The fractal characteristics of the blast-affected region form a unity with the three-dimensional roughness evaluation of the fissure surface.展开更多
The divergence three-dimensional millet-seed body model and the continuous distributing layer-imitating model were introduced, which were used to express geologic body, and the procedure of generating these two models...The divergence three-dimensional millet-seed body model and the continuous distributing layer-imitating model were introduced, which were used to express geologic body, and the procedure of generating these two models and their merits and demerits were synthesized. Three methods of geologic body’s three-dimensional expression were separately introduced, and the merits of the continuous distributing layer imitating model were proposed as comparing with the divergence three-dimensional millet-seed body model. The three-dimensional cubes were observed from any direction and any tangle with the application of dealing methods such as peeling, hollowing out, transparent or half-transparent.展开更多
BACKGROUND： The accurate measurements of various data of the bone diameters of foramen ovale of living person can change the methods of puncturing trigeminal gasserian ganglion via foramen ovale for treating trifacia...BACKGROUND： The accurate measurements of various data of the bone diameters of foramen ovale of living person can change the methods of puncturing trigeminal gasserian ganglion via foramen ovale for treating trifacial neuralgia from the experience of puncture operator only to puncture by taking the objective data of measurement as the evidence, which is good for improving the accuracy of puncturing trigeminal ganglion and reducing side effects. OBJECTIVE ： To observe the forms of foramen ovales in healthy adults displayed by volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan of skull base, and measure the longitudinal diameter and transverse diameter. DESIGN ： A repetitive observation and measurement SETTINGS ： Department of Neurosurgery and Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine. PARTICIPANTS： Fifty healthy adults （100 sides）, who were examined with three-dimensional spiral CT scan, were randomly selected from the Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine from January 2005 to January 2006, including 26 males and 24 females, aged 25-68 years with an average of 48 years old. They were all informed and agreed with the examination. METHODS ： The subjects were examined with the Philips 16-slice spiral CT-Mx 8000 IDT CT apparatus （Philips Company, Holland）, the scanning ranged from 2 cm below the canthomeatal line to the level of suprasellar cistem. The width of collimator was 0.75 mm, pitch was 0.663; tube current was 350 mA, voltage was 120 kV, resolution was 512×512 matrix; slice thickness of reconstruction was 1 mm, and interval was 0.5 mm. After the three-dimensional spiral CT thin-slice scan of skull base, the image post-processing techniques including volume rendering and multi-planar reconstruction were applied to observe the forms of foramen ovales, and measure the size, longitudinal diameter and transverse diameter of the foramen ovales. The figures of the foramen ovales were drawn with mouse along the boundary of bone porous margin and soft tissue. According to the indications, the diameters were measured with computer to observe the forms of foramen ovales. MAIN OUTCOME MEASURES ： The longitudinal diameter, transverse diameter and form of foramen ovales were observed. RESULTS： All the 50 healthy adults （100 sides） were involved in the analysis of results. （1） It was observed in the volume rendering images that foramen ovales had four forms of oval shape （77 sides）, kidney shape （12 sides）, round shape （7 sides）, ribbon shape （4 sides）. （2） The longitudinal diameters of left and right foramen ovales were （7.67±1.32） and （7.98±1.45） mm, and the transverse diameters were （4.04±0.83）, （4.09±1.07） mm; There was no obvious difference between left and right longitudinal diameters （t = 1.63, P = 0.11 ）, and left and right transverse diameters were close （t = 0.45, P= 0.65）. CONCLUSION ： The non-invasive techniques of volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan can clearly display the formand size of foramen ovale in healthy adults.展开更多
Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser sca...Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser scanning technology.Based on the practical application,this paper puts forward the discussion of related problems and matters needing attention.This has a certain reference significance for the study of new technology in surveying and mapping of ancient buildings.展开更多
Objective To explore three-dimensional relations of pedicle screw channel (PSC) ,screw entry point and lateral surface of cervical vertebral body by digital techniques. Methods CT scan images of cervical
By using the Somigliana representation and the concepts offinite-part integrals, a set of hypersingular integral equations ofthe interaction between two parallel planar cracks in a three-dimen-sional finite body subje...By using the Somigliana representation and the concepts offinite-part integrals, a set of hypersingular integral equations ofthe interaction between two parallel planar cracks in a three-dimen-sional finite body subjected to arbitrary loads is derived, and thenits numerical method is proposed by the finite-part integral methodcombined with the boundary element method. According to the analytictheory of hypersingular integral equations, the square root models ofdisplacement discontinuities in the elements near the crack front areapplied, and thus the computational precision is raised. Based onthis, the stress intensity factors can be directly calculated.Finally, the stress intensity factors of sever- al typicalinteraction problems are calculated.展开更多
In the terahertz（THz） band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compens...In the terahertz（THz） band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed.展开更多
Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving（LTCC） mining technology is studied by using self-developed three-dimensional（3D） test device. The loose top-c...Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving（LTCC） mining technology is studied by using self-developed three-dimensional（3D） test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also observed in the controlled test, which is verified that the deflection of drawing body is caused by shield. It is found that the deflection angle decreases with increasing caving height, with the maximum value of atailand the minimum value of 0. In addition, the formula to calculate the drawing volume is proposed subsequently.The deflection of drawing body is numerically simulated using particle flow code PFC3 Dand the proposed formula to calculate drawing volume in LTCC is also verified.展开更多
Melanosomes, isolated by centrifugal separation from culture broth of B16 melanoma cells derived from mouse, were observed by scanning electron microscopy (SEM), and by transmission electron microscopy (TEM). Some int...Melanosomes, isolated by centrifugal separation from culture broth of B16 melanoma cells derived from mouse, were observed by scanning electron microscopy (SEM), and by transmission electron microscopy (TEM). Some interesting structural features were found inside and outside of the melanosomes. By SEM observation, the melanosomes were ellipsoid shape, their surface was not smooth and was covered with rough substructure, 10 to 20 nm particles. By TEM, uneven structure and micro particles were observed in the melanosomes. Furthermore, three-dimensional analysis was tried by using the ultra-high voltage electron microscopy(UHVEM). Micrographs of the melanosomes were taken at various tilted angles by UHVEM, after preparing 500 nm thickness specimens stained with lead citrate. From the micrographs collected, the three-dimensional structures were reconstructed by using i-mode software. Melanin stained by lead and non stained parts was clearly observed in the reconstructed structure. Non stained parts were round, regular size, and distributed widely in the melanosomes.展开更多
To quantify the genetic correlations between total body fat mass （TBFM） and femoral neck geometric parameters （FNGPs） and, if pos- sible, to detect the specific genomic regions shared by them, bivariate genetic an...To quantify the genetic correlations between total body fat mass （TBFM） and femoral neck geometric parameters （FNGPs） and, if pos- sible, to detect the specific genomic regions shared by them, bivariate genetic analysis and bivariate whole-genome linkage scan were carried out in a large Caucasian population. All the phenotypes studied were significantly controlled by genetic factors （P 〈 0.001） with the heritabilities ranging from 0.45 to 0.68. Significantly genetic correlations were found between TBFM and CSA （cross-section area）, W （sub-periosteal diameter）, Z （section modulus） and CT （cortical thickness） except between TBFM and BR （buckling ratio）. The peak bivariate LOD scores were 3.23 （20q12）, 2.47 （20p11）, 3.19 （6q27）, 1.68 （20p12）, and 2.47 （7q11） for the five pairs of TBFM and BR, CSA, CT, W, and Z in the entire sample, respectively. Gender-specific bivariate linkage evidences were also found for the five pairs. 6p25 had complete pleiotropic effects on the variations of TBFM ＆ Z in the female sub-population, and 6q27 and 17q11 had coincident link- ages for TBFM ＆ CSA and TBFM ＆ Z in the entire population. We identified moderate genetic correlations and several shared genomic regions between TBFM and FNGPs in a large Caucasian population.展开更多
Based on the analysis of the principles of frequency-phase scanning 3-D （three-dimensional） radar and the scattering mechanism of 3-D radar, the target and clutter IF （intermediate frequency） signals model of freq...Based on the analysis of the principles of frequency-phase scanning 3-D （three-dimensional） radar and the scattering mechanism of 3-D radar, the target and clutter IF （intermediate frequency） signals model of frequencyphase scanning 3-D radar is presented. The IF signals model of different channels of 3-D radar is presented in one simple formula in which complex waveform effects are considered. The simulation results obtained during tests are also provided in the end.展开更多
In order to reveal the appearance of the clothing prototype on the human body,the characteristics of the human body’s structure above the waist section were studied.Based on the experimental data of the fit prototype...In order to reveal the appearance of the clothing prototype on the human body,the characteristics of the human body’s structure above the waist section were studied.Based on the experimental data of the fit prototype,three-dimensional prototypes features were comparatively analyzed.And then objectively evaluating the relationship was conducted between the planar structure lines of different prototypes and the human body.The results showed that the prototypes analyzed basically conformed to the size of the human body.However,when they were worn on the human body,there were problems in the structure and forming.The main reason was that the side seam was skewed to different degrees.The results of this study provide reference for many practitioners to choose prototypes.展开更多
To address the challenge of visualizing internal defects within castings, ultrasonic nondestructive testing technology has been introduced for the detection and characterization of internal defects in castings. Ultras...To address the challenge of visualizing internal defects within castings, ultrasonic nondestructive testing technology has been introduced for the detection and characterization of internal defects in castings. Ultrasonic testing is widely utilized for detecting and characterizing internal defects in materials, thanks to its strong penetration ability, wide testing area, and fast scanning speed. However, traditional ultrasonic testing primarily relies on one-dimensional waveforms or two-dimensional images to analyze internal defects in billets, which hinders intuitive characterization of defect quantity, size, spatial distribution, and other relevant information. Consequently, a three-dimensional (3D) layered characterization method of billets internal quality based on scanning acoustic microscope (SAM) is proposed. The method starts with a layered focus scanning of the billet using SAM and pre-processing the obtained sequence of ultrasonic images. Next, the ray casting is employed to reconstruct 3D shape of defects in billets, allowing for characterization of their quality by obtaining characteristic information on defect spatial distributions, quantity, and sizes. To validate the effectiveness of the proposed method, specimens of 42CrMo billets are prepared using five different processes, and the method is employed to evaluate their internal quality. Finally, a comparison between the ultrasonic image and the metallographic image reveals a difference in dimensional accuracy of only 2.94%. The results indicate that the new method enables visualization of internal defect information in billets, serving as a valuable complement to the traditional method of characterizing their internal quality.展开更多
In order to meet the requirements of nondestructive testing of true 3D topography of micro-nano structures,a novel three-dimensional atomic force microscope(3D-AFM)based on flared tip is developed.A high-precision sca...In order to meet the requirements of nondestructive testing of true 3D topography of micro-nano structures,a novel three-dimensional atomic force microscope(3D-AFM)based on flared tip is developed.A high-precision scanning platform is designed to achieve fast servo through moving probe and sample simultaneously,and several combined nanopositioning stages are used to guarantee linearity and orthogonality of displacement.To eliminate the signal deviation caused by AFM-head movement,a traceable optical lever system is designed for cantilever deformation detection.In addition,a method of tailoring the cantilever of commercial probe with flared tip is proposed to reduce the lateral force applied on the tip in measurement.The tailored probe is mounted on the 3D-AFM,and 3D imaging experiments are conducted on different samples by use of adaptive-angle scanning strategy.The results show the roob-mean-square value of the vertical displacement noise(RMS)of the prototype is less than 0.1 nm and the high/width measurement repeatability(peak-to-peak)is less than 2.5 nm.展开更多
Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing techn...Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing technologies can hardly create complex fracture networks because of their particular engineering and geological characteristics.In order to realize the efficient three-dimensional development of deep and ultra-deep marine carbonate oil and gas reservoirs,this paper revealed the acid fracturing difficulties of this kind of reservoirs based on the engineering and geological characteristics of deep marine carbonate oil and gas reservoirs in China.Then,by taking the efficient three-dimensional development of deep and ultra-deep marine carbonate oiland gas reservoirs as the target,the technical conceptof three-dimensional acid fracturing(3D-AF)was putforward based on the techniques of volume acid fracturing and deep acid fracturing.In addition,its technical connotation was il lustrated,and its key technologies were described in detail.Finally,its development direction in the next step was pointed out.And the following research results were obtained.First,the 3D-AF technology contains three basic connotations:(1)selecting the corresponding acid penetration technology according to reservoir types so as to realize sufficient resarvoir stimulation on the plane;(2)creating complex acid-fracture volume with higher flow conductivity under high closed pressure;(3)deploying acid-fracture volume rationally along the long hole section so as to realize sufficient reservoir stimulation in the wellbore direction.Second,there are three key technologies of 3D-AF,i.e.,the technology for predicting the effective acid-penetrate distance under the coupling action of multi-feld,multi-scale and multi-fluid,the technology for optimizing the flow conductivity of complex acid-fracture volume,and the technology for precisely deploying acid in the long section of horizontal well or highly deviated well.Third,in order to promote the further development of 3D-AFtechnology,it is necessary to carry out researches on three technologies,i.e.,the technology for predicting and reducing the fracturing pressure of ultra-deep reservoir,the tech-nology for predicting the geometry of acid-fracture body ina strongly heterogeneous reservoir,and the staged reservoir production technology and new fluid technology with high temperature resistance,low reaction rate and low friction resistance coefficient for long hole sections(over 7000 m).展开更多
Three-dimensional(3D)profile scanning plays a crucial role in the inspection of assembled large aircraft.In this paper,to achieve noncontact automatic measurements of the high-reflective profiles of large-scale curved...Three-dimensional(3D)profile scanning plays a crucial role in the inspection of assembled large aircraft.In this paper,to achieve noncontact automatic measurements of the high-reflective profiles of large-scale curved parts and components,an automated noncontact system and method with high accuracy and high efficiency are presented.First,a hybrid 3D coordinate measurement system based on proximity sensors and cameras is proposed to obtain noncontact measurements while avoiding the influence of high reflection on the measurement accuracy.A hybrid measurement model that combines the one-dimensional distances measured by the proximity sensors and the 3D information obtained by cameras is proposed to determine high-accuracy 3D coordinates of the measured points.Then,a profile-driven 3D automated scanning method and strategy are designed to rapidly scan and reconstruct the profile within the effective range without scratching the profile or exceeding the measurement range of the proposed system.Finally,experiments and accuracy analyses are performed in situ on an assembled tailplane panel(approximately 1760 mm×460 mm).The automated scanning process is completed in a timeframe of 208s with an average error of less than 0.121 mm for profile reconstruction.Therefore,the proposed method is promising considering both the high accuracy and high efficiency requirements of profile inspections for large aircraft.展开更多
基金Project(51274250)supported by the National Natural Science Foundation of ChinaProject(2012BAK09B02-05)supported by the National Key Technology R&D Program during the 12th Five-year Plan of China
文摘An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.
基金supported by the China Geological Survey (No.1212011014030)the Major State Basic Research Development Program of China (973 Program) (No.2011CB710600)
文摘The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation methods, a new approach based on the shadow area percentage （SAP） that can be used to quantify surface roughness is proposed in this article. Firstly, by the help of laser scanning technique, the three-dimensional model of the surface of rock discontinuity was established. Secondly, a light source was simulated, and there would be some shadows produced on the model surface. Thirdly, to obtain the value of SAP of each specimen, the shadow detection technique was introduced for use. Fourthly, compared with the result from direct shear testing and based on statistics, an empirical for- mula was found among SAP, normal stress, and shear strength. Data of Yujian （~ River were used as an example, and the following conclusions have been made. （1） In the case of equal normal stress, the peak shear stress is positively proportional to the SAP. （2） The formula for estimating was derived, and the predictions of peak-shear strength made with this equation well agreed with the experimental re- suits obtained in laboratory tests.
基金National Natural Science Foundation of China(Grant No.51804318)the China Postdoctoral Science Foundation Founded Project(Grant No.2019M650963)National Key Basic Research and Development Program of China(Grant No.2014CB239203).
文摘Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFC2902103National Natural Science Foundation of China,Grant/Award Number:51934001Fundamental Research Funds for the Central Universities,Grant/Award Number:2023JCCXLJ02。
文摘Fracture surface contour study is one of the important requirements for characterization and evaluation of the microstructure of rocks.Based on the improved cube covering method and the 3D contour digital reconstruction model,this study proposes a quantitative microstructure characterization method combining the roughness evaluation index and the 3D fractal dimension to study the change rule of the fracture surface morphology after blasting.This method was applied and validated in the study of the fracture microstructure of the rock after blasting.The results show that the fracture morphology characteristics of the 3D contour digital reconstruction model have good correlation with the changes of the blasting action.The undulation rate of the three-dimensional surface profile of the rock is more prone to dramatic rise and dramatic fall morphology.In terms of tilting trend,the tilting direction also shows gradual disorder,with the tilting angle increasing correspondingly.All the roughness evaluation indexes of the rock fissure surface after blasting show a linear and gradually increasing trend as the distance to the bursting center increases;the difference between the two-dimensional roughness evaluation indexes and the three-dimensional ones of the same micro-area rock samples also becomes increasingly larger,among which the three-dimensional fissure roughness coefficient JRC and the surface roughness ratio Rs display better correlation.Compared with the linear fitting formula of the power function relationship,the three-dimensional fractal dimension of the postblast fissure surface is fitted with the values of JRC and Rs,which renders higher correlation coefficients,and the degree of linear fitting of JRC to the three-dimensional fractal dimension is higher.The fractal characteristics of the blast-affected region form a unity with the three-dimensional roughness evaluation of the fissure surface.
基金Project supported by the Opening Foundation of the Key Lab of Resource , Environment and GISin Beijing
文摘The divergence three-dimensional millet-seed body model and the continuous distributing layer-imitating model were introduced, which were used to express geologic body, and the procedure of generating these two models and their merits and demerits were synthesized. Three methods of geologic body’s three-dimensional expression were separately introduced, and the merits of the continuous distributing layer imitating model were proposed as comparing with the divergence three-dimensional millet-seed body model. The three-dimensional cubes were observed from any direction and any tangle with the application of dealing methods such as peeling, hollowing out, transparent or half-transparent.
基金a grant fromTackle Key Problems in Sci-ence and Technology of FoshanCity, No. 200505075
文摘BACKGROUND： The accurate measurements of various data of the bone diameters of foramen ovale of living person can change the methods of puncturing trigeminal gasserian ganglion via foramen ovale for treating trifacial neuralgia from the experience of puncture operator only to puncture by taking the objective data of measurement as the evidence, which is good for improving the accuracy of puncturing trigeminal ganglion and reducing side effects. OBJECTIVE ： To observe the forms of foramen ovales in healthy adults displayed by volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan of skull base, and measure the longitudinal diameter and transverse diameter. DESIGN ： A repetitive observation and measurement SETTINGS ： Department of Neurosurgery and Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine. PARTICIPANTS： Fifty healthy adults （100 sides）, who were examined with three-dimensional spiral CT scan, were randomly selected from the Department of Medical Imaging, Foshan Hospital of Traditional Chinese Medicine from January 2005 to January 2006, including 26 males and 24 females, aged 25-68 years with an average of 48 years old. They were all informed and agreed with the examination. METHODS ： The subjects were examined with the Philips 16-slice spiral CT-Mx 8000 IDT CT apparatus （Philips Company, Holland）, the scanning ranged from 2 cm below the canthomeatal line to the level of suprasellar cistem. The width of collimator was 0.75 mm, pitch was 0.663; tube current was 350 mA, voltage was 120 kV, resolution was 512×512 matrix; slice thickness of reconstruction was 1 mm, and interval was 0.5 mm. After the three-dimensional spiral CT thin-slice scan of skull base, the image post-processing techniques including volume rendering and multi-planar reconstruction were applied to observe the forms of foramen ovales, and measure the size, longitudinal diameter and transverse diameter of the foramen ovales. The figures of the foramen ovales were drawn with mouse along the boundary of bone porous margin and soft tissue. According to the indications, the diameters were measured with computer to observe the forms of foramen ovales. MAIN OUTCOME MEASURES ： The longitudinal diameter, transverse diameter and form of foramen ovales were observed. RESULTS： All the 50 healthy adults （100 sides） were involved in the analysis of results. （1） It was observed in the volume rendering images that foramen ovales had four forms of oval shape （77 sides）, kidney shape （12 sides）, round shape （7 sides）, ribbon shape （4 sides）. （2） The longitudinal diameters of left and right foramen ovales were （7.67±1.32） and （7.98±1.45） mm, and the transverse diameters were （4.04±0.83）, （4.09±1.07） mm; There was no obvious difference between left and right longitudinal diameters （t = 1.63, P = 0.11 ）, and left and right transverse diameters were close （t = 0.45, P= 0.65）. CONCLUSION ： The non-invasive techniques of volume rendering and multi-planar reconstruction after three-dimensional spiral CT thin-slice scan can clearly display the formand size of foramen ovale in healthy adults.
基金Jiangxi Social Science Planning Project:Research on the Activation of Traditional Villages in Jiangxi Province from the Perspective of Cultural Conservation:A Case Study of Fuhe River Basin(Grant No.17BJ16).
文摘Based on the study of the application of three-dimensional laser scanning technology in ancient building surveying and mapping,this paper briefly describes the working principle and flow of three-dimensional laser scanning technology.Based on the practical application,this paper puts forward the discussion of related problems and matters needing attention.This has a certain reference significance for the study of new technology in surveying and mapping of ancient buildings.
文摘Objective To explore three-dimensional relations of pedicle screw channel (PSC) ,screw entry point and lateral surface of cervical vertebral body by digital techniques. Methods CT scan images of cervical
文摘By using the Somigliana representation and the concepts offinite-part integrals, a set of hypersingular integral equations ofthe interaction between two parallel planar cracks in a three-dimen-sional finite body subjected to arbitrary loads is derived, and thenits numerical method is proposed by the finite-part integral methodcombined with the boundary element method. According to the analytictheory of hypersingular integral equations, the square root models ofdisplacement discontinuities in the elements near the crack front areapplied, and thus the computational precision is raised. Based onthis, the stress intensity factors can be directly calculated.Finally, the stress intensity factors of sever- al typicalinteraction problems are calculated.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.YYYJ-1123)
文摘In the terahertz（THz） band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed.
基金financially supported by the Coal Joint Funds of the National Natural Science Foundation of China(No.U1361209)the National Basic Research Program of China(973 Program)(No.2013CB227903)
文摘Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving（LTCC） mining technology is studied by using self-developed three-dimensional（3D） test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also observed in the controlled test, which is verified that the deflection of drawing body is caused by shield. It is found that the deflection angle decreases with increasing caving height, with the maximum value of atailand the minimum value of 0. In addition, the formula to calculate the drawing volume is proposed subsequently.The deflection of drawing body is numerically simulated using particle flow code PFC3 Dand the proposed formula to calculate drawing volume in LTCC is also verified.
文摘Melanosomes, isolated by centrifugal separation from culture broth of B16 melanoma cells derived from mouse, were observed by scanning electron microscopy (SEM), and by transmission electron microscopy (TEM). Some interesting structural features were found inside and outside of the melanosomes. By SEM observation, the melanosomes were ellipsoid shape, their surface was not smooth and was covered with rough substructure, 10 to 20 nm particles. By TEM, uneven structure and micro particles were observed in the melanosomes. Furthermore, three-dimensional analysis was tried by using the ultra-high voltage electron microscopy(UHVEM). Micrographs of the melanosomes were taken at various tilted angles by UHVEM, after preparing 500 nm thickness specimens stained with lead citrate. From the micrographs collected, the three-dimensional structures were reconstructed by using i-mode software. Melanin stained by lead and non stained parts was clearly observed in the reconstructed structure. Non stained parts were round, regular size, and distributed widely in the melanosomes.
基金supported by grants from NIH in USA (No. K01 AR02170-01, R01 AR45349-01, R01 GM60402-01 A1, R01 AG026564-01A2, and R21 AG027110-01A1)the Natural Science Foundation o China (NSFC) (No. 30600364)The genotyping experiment was performed by Marshfield Center for Medical Genetics and supported by NHLB Mammalian Genotyping Service (Contract No. HV48141)
文摘To quantify the genetic correlations between total body fat mass （TBFM） and femoral neck geometric parameters （FNGPs） and, if pos- sible, to detect the specific genomic regions shared by them, bivariate genetic analysis and bivariate whole-genome linkage scan were carried out in a large Caucasian population. All the phenotypes studied were significantly controlled by genetic factors （P 〈 0.001） with the heritabilities ranging from 0.45 to 0.68. Significantly genetic correlations were found between TBFM and CSA （cross-section area）, W （sub-periosteal diameter）, Z （section modulus） and CT （cortical thickness） except between TBFM and BR （buckling ratio）. The peak bivariate LOD scores were 3.23 （20q12）, 2.47 （20p11）, 3.19 （6q27）, 1.68 （20p12）, and 2.47 （7q11） for the five pairs of TBFM and BR, CSA, CT, W, and Z in the entire sample, respectively. Gender-specific bivariate linkage evidences were also found for the five pairs. 6p25 had complete pleiotropic effects on the variations of TBFM ＆ Z in the female sub-population, and 6q27 and 17q11 had coincident link- ages for TBFM ＆ CSA and TBFM ＆ Z in the entire population. We identified moderate genetic correlations and several shared genomic regions between TBFM and FNGPs in a large Caucasian population.
文摘Based on the analysis of the principles of frequency-phase scanning 3-D （three-dimensional） radar and the scattering mechanism of 3-D radar, the target and clutter IF （intermediate frequency） signals model of frequencyphase scanning 3-D radar is presented. The IF signals model of different channels of 3-D radar is presented in one simple formula in which complex waveform effects are considered. The simulation results obtained during tests are also provided in the end.
文摘In order to reveal the appearance of the clothing prototype on the human body,the characteristics of the human body’s structure above the waist section were studied.Based on the experimental data of the fit prototype,three-dimensional prototypes features were comparatively analyzed.And then objectively evaluating the relationship was conducted between the planar structure lines of different prototypes and the human body.The results showed that the prototypes analyzed basically conformed to the size of the human body.However,when they were worn on the human body,there were problems in the structure and forming.The main reason was that the side seam was skewed to different degrees.The results of this study provide reference for many practitioners to choose prototypes.
基金supported by the joint funds of the National Natural Science Foundation of China (Grant No. U22A20186)the Open Foundation of Key Laboratory of Metallurgical Equipment and Control Technology (Wuhan University of Science and Technology) Ministry of Education (Grant No. MECOF2019804)the Foundation of Key Technologies R&D Program of Guangdong Province (Grant No. 2020B0101130007).
文摘To address the challenge of visualizing internal defects within castings, ultrasonic nondestructive testing technology has been introduced for the detection and characterization of internal defects in castings. Ultrasonic testing is widely utilized for detecting and characterizing internal defects in materials, thanks to its strong penetration ability, wide testing area, and fast scanning speed. However, traditional ultrasonic testing primarily relies on one-dimensional waveforms or two-dimensional images to analyze internal defects in billets, which hinders intuitive characterization of defect quantity, size, spatial distribution, and other relevant information. Consequently, a three-dimensional (3D) layered characterization method of billets internal quality based on scanning acoustic microscope (SAM) is proposed. The method starts with a layered focus scanning of the billet using SAM and pre-processing the obtained sequence of ultrasonic images. Next, the ray casting is employed to reconstruct 3D shape of defects in billets, allowing for characterization of their quality by obtaining characteristic information on defect spatial distributions, quantity, and sizes. To validate the effectiveness of the proposed method, specimens of 42CrMo billets are prepared using five different processes, and the method is employed to evaluate their internal quality. Finally, a comparison between the ultrasonic image and the metallographic image reveals a difference in dimensional accuracy of only 2.94%. The results indicate that the new method enables visualization of internal defect information in billets, serving as a valuable complement to the traditional method of characterizing their internal quality.
基金National Key Research and Development Pragram of China(No.2016YFF0200602)National Natural Science Foundation of China(No.61973233)。
文摘In order to meet the requirements of nondestructive testing of true 3D topography of micro-nano structures,a novel three-dimensional atomic force microscope(3D-AFM)based on flared tip is developed.A high-precision scanning platform is designed to achieve fast servo through moving probe and sample simultaneously,and several combined nanopositioning stages are used to guarantee linearity and orthogonality of displacement.To eliminate the signal deviation caused by AFM-head movement,a traceable optical lever system is designed for cantilever deformation detection.In addition,a method of tailoring the cantilever of commercial probe with flared tip is proposed to reduce the lateral force applied on the tip in measurement.The tailored probe is mounted on the 3D-AFM,and 3D imaging experiments are conducted on different samples by use of adaptive-angle scanning strategy.The results show the roob-mean-square value of the vertical displacement noise(RMS)of the prototype is less than 0.1 nm and the high/width measurement repeatability(peak-to-peak)is less than 2.5 nm.
基金supported by the National Natural Science Foundation of China"Research on acidizing mechanism under the coupling of temperature,fracture flow,acid-rock reaction,and stress damage for fractured carbonate rocks"(No.51704249)National Natural Science Foundation of China"Acid fracturing of low-permeability and tight oil and gas reservoirs"(No.51525404)the China Postdoctoral Science Foundation-General Program Research on acidizing mechanism of fracture network in deep,high-temperature,fractured carbonat rocks"(No.2017M623063).
文摘Acid fracturing is an indispensable technology in the efficient development of carbonate oil and gas rosarvoirs.As for deep and ultra-deep marine carbonate oil and gas reservoirs,however,existing acid fracturing technologies can hardly create complex fracture networks because of their particular engineering and geological characteristics.In order to realize the efficient three-dimensional development of deep and ultra-deep marine carbonate oil and gas reservoirs,this paper revealed the acid fracturing difficulties of this kind of reservoirs based on the engineering and geological characteristics of deep marine carbonate oil and gas reservoirs in China.Then,by taking the efficient three-dimensional development of deep and ultra-deep marine carbonate oiland gas reservoirs as the target,the technical conceptof three-dimensional acid fracturing(3D-AF)was putforward based on the techniques of volume acid fracturing and deep acid fracturing.In addition,its technical connotation was il lustrated,and its key technologies were described in detail.Finally,its development direction in the next step was pointed out.And the following research results were obtained.First,the 3D-AF technology contains three basic connotations:(1)selecting the corresponding acid penetration technology according to reservoir types so as to realize sufficient resarvoir stimulation on the plane;(2)creating complex acid-fracture volume with higher flow conductivity under high closed pressure;(3)deploying acid-fracture volume rationally along the long hole section so as to realize sufficient reservoir stimulation in the wellbore direction.Second,there are three key technologies of 3D-AF,i.e.,the technology for predicting the effective acid-penetrate distance under the coupling action of multi-feld,multi-scale and multi-fluid,the technology for optimizing the flow conductivity of complex acid-fracture volume,and the technology for precisely deploying acid in the long section of horizontal well or highly deviated well.Third,in order to promote the further development of 3D-AFtechnology,it is necessary to carry out researches on three technologies,i.e.,the technology for predicting and reducing the fracturing pressure of ultra-deep reservoir,the tech-nology for predicting the geometry of acid-fracture body ina strongly heterogeneous reservoir,and the staged reservoir production technology and new fluid technology with high temperature resistance,low reaction rate and low friction resistance coefficient for long hole sections(over 7000 m).
基金supported in part by project of National Key R&D Program of China(2018YFA0703304)National Natural Science Foundation of China(U1808217)+1 种基金Youth Program of National Natural Science Foundation of China(51905077)Liaoning Revitalization Talents Program(XLYC1807086)。
文摘Three-dimensional(3D)profile scanning plays a crucial role in the inspection of assembled large aircraft.In this paper,to achieve noncontact automatic measurements of the high-reflective profiles of large-scale curved parts and components,an automated noncontact system and method with high accuracy and high efficiency are presented.First,a hybrid 3D coordinate measurement system based on proximity sensors and cameras is proposed to obtain noncontact measurements while avoiding the influence of high reflection on the measurement accuracy.A hybrid measurement model that combines the one-dimensional distances measured by the proximity sensors and the 3D information obtained by cameras is proposed to determine high-accuracy 3D coordinates of the measured points.Then,a profile-driven 3D automated scanning method and strategy are designed to rapidly scan and reconstruct the profile within the effective range without scratching the profile or exceeding the measurement range of the proposed system.Finally,experiments and accuracy analyses are performed in situ on an assembled tailplane panel(approximately 1760 mm×460 mm).The automated scanning process is completed in a timeframe of 208s with an average error of less than 0.121 mm for profile reconstruction.Therefore,the proposed method is promising considering both the high accuracy and high efficiency requirements of profile inspections for large aircraft.
