With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dan...With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dangerous mountainous areas under the premise of ensuring the safety of personnel while restoring the real geographic information as much as possible. However, geological disaster areas are often accompanied by many adverse factors such as cliffs and dense vegetation. Based on this, the paper introduced the flight line design of oblique photogrammetry, analyzed the multi-platform data fusion processing, studied the multi-period data dynamic evaluation technology and proposed the application methods of data acquisition, early warning, disaster assessment and decision management suitable for geological disaster identification through the analysis of actual cases, which will help geologists to plan and control geological work more scientifically and rationally, improve work efficiency and reduce the potential personnel safety hazards in the process of geological survey, to offer technical support to the application of oblique photogrammetry in geological disaster identification and decision making and provide the scientific basis for personal and property safety protection and later-stage geological disaster management in disaster areas.展开更多
This study is aimed to explore the clinical application of the guiding template designed by three-dimensional printing data for the insertion of sacroiliac screws.A retrospective study of 7 cases (from July 2016 to De...This study is aimed to explore the clinical application of the guiding template designed by three-dimensional printing data for the insertion of sacroiliac screws.A retrospective study of 7 cases (from July 2016 to December 2016),in which the guiding template printed by the three-dimensional printing technique was used for the insertion of sacroiliac screws of patients with posterior ring injuries of pelvis,was performed.Totally,4 males and 3 females were included in template group,aged from 38to 65years old (mean 50.86±8.90).Of them,5 had sacral fractures (3 with Denis type Ⅰ and 2 with type Ⅱ)and 2 the separation of sacroiliac joint.Guiding templates were firstly made by the three-dimensional printing technique based on the pre-operative CT data. Surgical operations for the stabilization of pelvic ring by applying the guiding templates were carried out.A group of 8 patients with sacroiliac injuries treated by percutaneous sacroiliac screws were analyzed as a control group retrospectively.The time of each screw insertion,volume of intra-operative blood loss,and the exposure to X ray were analyzed and the Matta's radiological criteria were used to evaluate the reduction quality.The Majeed score was used to evaluate postoperative living quality.The visual analogue scale (VAS)was applied at different time points to judge pain relief of coccydynia.All the 7 patients in the template group were closely followed up radiographically and clinically for 14 to 20 months,mean (16.57±2.44)months.Totally 9 sacroiliac screws for the S 1 and S2 vertebra were inserted in the 7 patients.The time length for each screw insertion ranged from 450 to 870 s,mean (690.56±135.68)s,and the number of times of exposure to X ray were 4 to 8,mean (5.78±1.20).The intra-operative blood loss ranged from 45to 120 mL,mean (75±23.32)mL.According to Matta's radiology criteria,the fracture and dislocation reduction were excellent in 6cases and good in 1.The pre-operative VAS score ranged from 5.2 to 8.1,mean (7.13±1.00).The average one-week/six-month post-operative VAS was (5.33±0.78)and (1.33±0.66),respectively (P<0.05 when compared with pre-operative VAS).The 12-month post-operative Majeed score ranged from 86 to 92,mean (90.29±2.21).The three-dimensional printed guiding template for sacroiliac screw insertion,which could significantly shorten the operation time,provide a satisfied outcome of the stabilization of the pelvic ring,and protect doctors and patients from X-ray exposure,might be a practical and valuable new clinical technique.展开更多
Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic...Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.展开更多
This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low...This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low-cost equipment for data acquisition. This study proposed the three-dimensional visualization of grapes and topography on Xi axes through the Moire projection technique. The artificial grapes with a 20 cm long bunch and 18.45 mm average diameter for each grape were used. A projector was used to generate a grid with light and dark lines. The grape bunch was placed on a holder, illuminated by a sinusoidal grid and photographed. After processing the images, a three-dimensional map of the fruit and topography on Xi axes were obtained. The three-dimensional fruit observation allows the visualization of the higher and lower regions of the three-dimensional configuration through a color map. This result makes it possible to obtain size and shape of the grape bunch, allowing for the process automation of product selection and classification.展开更多
Heart diseases remain the top threat to human health,and the treatment of heart diseases changes with each passing day.Convincing evidence shows that three-dimensional(3D)printing allows for a more precise understandi...Heart diseases remain the top threat to human health,and the treatment of heart diseases changes with each passing day.Convincing evidence shows that three-dimensional(3D)printing allows for a more precise understanding of the complex anatomy associated with various heart diseases.In addition,3D-printed models of cardiac diseases may serve as effective educational tools and for hands-on simulation of surgical interventions.We introduce examples of the clinical applications of different types of 3D printing based on specific cases and clinical application scenarios of 3D printing in treating heart diseases.We also discuss the limitations and clinically unmet needs of 3D printing in this context.展开更多
The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual worklo...The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging(Micro-MRI), an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions(Mannerist Solution/GD-DTPA contrast agent, distilled water) were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent(Mannerist Solution/GD-DTPA) and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.展开更多
A new collapse model of the trapdoors,three-dimensional rectangular trapdoor(3DRT),is presented for ground surface collapse.Undrained stability of 3DRT is examined with the upper bound method of plasticity limit analy...A new collapse model of the trapdoors,three-dimensional rectangular trapdoor(3DRT),is presented for ground surface collapse.Undrained stability of 3DRT is examined with the upper bound method of plasticity limit analysis theory.The soil where the trapdoors are located is assumed to be a perfectly plastic model with a Tresca yield criterion.Block analysis technique is employed to investigate the collapse of 3DRT.The model is divided into five different block types and added up to ten rigid blocks.According to the law of conservation of energy,the critical stability ratios of 3DRT are obtained through a search proceeding.The results of upper bound solution for 3DRT are given,and three trapdoor models with depth various are discussed during the application in the stability analysis of square trapdoors.The critical stability ratios can be used in the design of underground excavation and support force.展开更多
Fluoro-ruby was injected into the posterior funiculus of the spinal cord in the cervical (C5-T2) and lumbar (L3-6) segments of adult guinea pigs. The spinal cord was cut into serial frozen sections. The Fluoro-rub...Fluoro-ruby was injected into the posterior funiculus of the spinal cord in the cervical (C5-T2) and lumbar (L3-6) segments of adult guinea pigs. The spinal cord was cut into serial frozen sections. The Fluoro-ruby labeling was clearly delineated from the surrounding structure. The labeling traversed the cervical, thoracic and lumbar segments, and was located on the ventral portion of the posterior funiculus on the injected side, proximal to the intermediate zone of the dorsal gray matter. The fluorescence area narrowed rostro-caudally. The spinal cord, spinal cord gray matter and corticospinal tract were reconstructed using 3D-DOCTOR 4.0 software, resulting in a robust three-dimensional profile. Using functionality provided by the reconstruction software, free multi-angle observation and sectioning could be conducted on the spinal cord and corticospinal tract. Our experimental findings indicate that the Fluoro-ruby retrograde fluorescent tracing technique can accurately display the anatomical location of corticospinal tract in the guinea pig and that three-dimensional reconstruction software can be used to provide a three-dimensional image of the corticospinal tract.展开更多
A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equatio...A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equations for salt, temperature and subgridscale energy, and an equation of state. In the model, according to the hypothesis of Kolmogorov and Prandtl, the viscosity coefficient of turbulent flow of homogeneous fluid is related to the local turbulent energy, and the horizontal and vertical exchange coefficients of mass, heat and momentum are computed with the introduction of subgridscale turbulence energy. The governing equations are solved by finite difference techniques. This model is applied to the Jiaozhou bay to predict thermal pollution by the Huangdao power plant. An instantaneous tidal current field is computed, then the distribution of temperature increment is predicted, and finally the effect of wind stress on thermal discharge is discussed.展开更多
The surgical removal of renal cancer,along with the thrombectomy of the inferior vena cava tumour thrombus,represents a remarkable milestone in urological surgery.This procedure is not only technically demanding but a...The surgical removal of renal cancer,along with the thrombectomy of the inferior vena cava tumour thrombus,represents a remarkable milestone in urological surgery.This procedure is not only technically demanding but also requires a high level of surgical expertise.Managing renal cancer combined with a vena cava tumour thrombus poses significant challenges,especially when dealing with combined grade Ⅱ-Ⅳ inferior vena cava tumour thrombus.The complexity of these cases is further exacerbated by the delicate anatomical structures involved and the need to preserve critical vessels while effectively removing the tumour.The Upper Urethral Tumour Treatment Centre of Weifang People's Hospital successfully treated a challenging case of left renal tumour combined with grade II inferior vena cava tumour thrombus.The surgical team,led by experienced urological surgeons,meticulously planned and executed the procedure,ensuring minimal trauma to the patient and complete removal of the tumour.This achievement not only demonstrates the hospital's commitment to providing state-of-the-art surgical care but also highlights the importance of continued research and training in urological oncology.The successful outcome of this case is a testament to the expertise and dedication of the medical team and offers hope to patients facing similar complex surgical challenges.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
Fenlong green ecological agriculture technology (Fenlong technology), a new smash ridging farming method developed by Guangxi Academy of Agdcultural Sciences, has been elected as the recommended cultivation techniqu...Fenlong green ecological agriculture technology (Fenlong technology), a new smash ridging farming method developed by Guangxi Academy of Agdcultural Sciences, has been elected as the recommended cultivation technique by the Ministry of Agriculture of China. It replaces the traditional plowshare with spiral drill, and its tilth depth is twice deeper than that by tractor tilthing. It also extends soil nutrient, moisture, oxygen and microorganism, the so-called "Four pools". Soil nutrient, oxygen, microorganism, light and rainfall use ratio is increased by 10%-100%, creating a platform for natural increase of more than 10% of crop yield. Its application to over 20 kinds of crops in 21 provinces has proved that the yield increases 10-30% with quality enhancing 5% and double water retaining capacity but no more input. When the application area of Fenlong could reach 67 million hm2, the amount of fertilizer can be reduced by 40-50 billion kg, saving 120-150 billion Yuan. In this paper, we put forward the strategy of "4+1" (arable, saline-alkali soil, grasslands, Sponge City + rivers) green development in China, and deepened the Fenlong cultivated tilled layer from 16.5 cm to 35 cm for 67 million hm2 arable land, ridged 13.3 million hm2 of saline-alkali soil for 35 cm, and also 35 cm for 67 million hm2 degraded steppe, which could have the following 3 effects: first, the 147 million hm2 of land with Fenlong cultivation could increase loosing soil to 315.491 billion m3, in* creasing by 159.26% for 120 million hm2 of arable land with the average tilled layer of 16.5 cm, which has loosing soil of only 198.1 billion m3, that is, the space of the land increases 1.6 times. Second, every hectare of plowland could store up to 450 m3/hm2 of natural rainfall, and the unused 60 m3 of saline-alkali soil and grasslands could store water of 102 billion m3, showing an increase of over 88.89% for the current plowland storage of 54 billion m3 at now, that is, double the natural rainfall storage capacity. Third, the two multiple increase of natural resources application can bring trillions of resource activation, environmental cleaning, food security, citizens, health, economic, ecological and social benefits, and makes the Chinese nation move forward in green development. Its application in "big scientific research" and "One Belt And One Road" will contribute Chinese strength to the world.展开更多
Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speck...Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.展开更多
Background:Radiological imaging plays a pivotal role in forensic anthropology.As have the imaging techniques advances,so have the digital skeletal measurements inched towards precision.Secular trends of the population...Background:Radiological imaging plays a pivotal role in forensic anthropology.As have the imaging techniques advances,so have the digital skeletal measurements inched towards precision.Secular trends of the population keep on changing in modem times.Hence,finding the precise technique of bone measurement,with greater reproducibility,in modem population is always needed in making population specific biological profile.Aim and Objective:The aim of this study was to estimate the accuracy of the foramen magnum measurement,obtained by three dimensional multi-detector computed tomography using volume rendering technique with the cut off value of each variable,in sex determination of an individual.Materials and Methods:Two metric traits,an antero-posterior diameter(APD)and transverse diameter(TD),were measured digitally in an analysis of 130 radiological images having equal proportion of male and female samples.Foramen magnum index and area of foramen magnum(Area by Radinsky's[AR],Area by Teixeira5s[AT])were derived from APD and TD.Results:Descriptive statistical analysis,using unpaired t-test,showed significant higher value in males in all the variables.Using Pearson correlation analysis,maximum correlation was observed between area(AT and AR r=0.999)and between area and TD(AR r=0.955 and AT r=0.945 respectively).When used individually,TD had the highest predictive value(67.7%)for sex detennination among all the parameters followed by AT(65.4%)and AR(64.6%).Cutoff value of variables TD,AR and AT were 29.9 mm,841.80 mm2 and 849.70 mm2 respectively.Receiver operating characteristic curve predicted male and female sex with 96.2%and 89.2%accuracy respectively.The overall accuracy of the model was 92.7%.Conclusion:Measurements from 3D CT using volume rendering technique were precise,and the application of logistic regression analysis predicted the sex with more accuracy.展开更多
Developments of digital technology and three-dimensional(3D)reconstruction allowed a precise description of anatomic structures.With the introduction of Visible Human Project and Virtual Chinese Human(VCH)techniques,m...Developments of digital technology and three-dimensional(3D)reconstruction allowed a precise description of anatomic structures.With the introduction of Visible Human Project and Virtual Chinese Human(VCH)techniques,more detailed anatomic images could be obtained.Digitized visible models of these structures can be applied as a useful tool in clinical training.The aim of this study was to reconstruct the normal structures of thoracodorsal artery in 3D images and to establish the digitized visible models of latissimus dorsi myocutaneous(LDM)flap.The cross-sectional images from the four VCH datasets were reviewed to study LDM and thoraco-dorsal artery structures on a section-by-section basis.Next,two adult fresh cadaver specimens were perfused with lead oxide-gelatine mixture and subject to radio-graphic CT scanning on their torsos.The cross-sectional images from the CT images were reviewed to study thor-acodorsal artery structures.Three-dimensional computer-ized reconstructions of LDM flap structures were conducted from these datasets by using Amira 3.1(TGS)software respectively.The 3D reconstructed visible models established from these datasets perfectly displayed the anatomic characteristics of LDM flap.展开更多
Objectives This study was to investigate the differences between modeling and non-modeling left atrium (LA) in CartoXP system guided catheter ablation for paroxysmal atrial fibrillation (PAF). Methods From Jan to ...Objectives This study was to investigate the differences between modeling and non-modeling left atrium (LA) in CartoXP system guided catheter ablation for paroxysmal atrial fibrillation (PAF). Methods From Jan to Dec in 2008 total 31 cases with PAF were enrolled. All were treated by the same electrophysiologist with CartoXP guidance. Catheter ablation was accomplished without left atrium and pulmonary veins modeling in 17 patients (non-modeling group) and with left atrium modeling in 14 patients (modeling group). The detailed ablation method was based on circumferential pulmonary veins isolation (CPVI). And linear ablation of tricuspid valvular isthmus was performed individually. The ablation endpoint was a complete isolation of pulmonary vein potential from left atrium and no further induced continuous fast atrial arrhythmia including atrial fibrillation (AF), atrial flutter (AFL) and atrial tachycardia (AT). Each step for the procedures and the follow-up outcomes were compared correspondingly. Results The total procedure time was 107.23 ± 28.92 min in modeling group vs 93.47 ±26.09 min in non-modeling group ( P 〉 0.05 ). The X-ray exposure time was significantly longer in modeling group (21.09 ±6. 49 rain) than in non-modeling group (14. 16 ± 5.35 min). The CPVI times of right pulmonary veins and left pulmonary veins were 28. 14 ± 9. 26 min was 27.29 ± 18.53 min in modeling group respectively, vs 18.00 ±4. 51 min and 23.94 ± 7. 10 min in non-modeling group respectively, (P 〈 0. 05 ). There is no significant difference between modeling group (85.7%) and non-modeling group (82.4%) over follow-up period of 2 to 13 months. Confusions CartoXP system guided catheter ablation of PAF without modeling of left atrium and pulmonary veins took less time in X-ray exposure and ablation steps, comparing with left atrium modeling procedure.展开更多
According to the question of how to transfer data between Pro/E and ADAMS correctly, the paper gives an improved importing solution, which combines the interface and the Standard Data Format(SDF) files. It settles t...According to the question of how to transfer data between Pro/E and ADAMS correctly, the paper gives an improved importing solution, which combines the interface and the Standard Data Format(SDF) files. It settles the problems caused by improper geometry during the import conducted by the interface software. With the solution ,fea- ture points can be conveniently picked to build kinematic constraints are the preparation of the model will be simpli- fied. An example is given for the method, and corresponding simulations are conducted. The results of the simula- tions verify the validity of the solution.展开更多
The quantification and effects of system pH value on the interactions between Pb(II) and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks (Ex/Em = 280 nm1...The quantification and effects of system pH value on the interactions between Pb(II) and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks (Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B). The fluorescence intensities of peak B were higher than those of peak A. The fluorophores of both peaks could be largely quenched by Pb(ll), and the quencher dose for peak B was about half of that for peak A. The modified Stern-Volmer equation well depicted the fluorescence quenching titration. The quenching constant (Ka) values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb(II) due to the occurrence of Pb(OH)2 sediments. The Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins (peak B) played a key role in the interactions between metal ions and the biopolymer.展开更多
Background CartoMerge has been widely used in guiding circumferential pulmonary vein isolation (CPVI) for the treatment of paroxysmal atrial fibrillation (PAF). However, the procedure of landmarks selection varies...Background CartoMerge has been widely used in guiding circumferential pulmonary vein isolation (CPVI) for the treatment of paroxysmal atrial fibrillation (PAF). However, the procedure of landmarks selection varies among operators according to their experience. Techniques have to be established to standardize this procedure. We propose that Overlay Ref could facilitate this procedure. This paper aimed to report our initial experience with CPVI guided by Overlay Ref and CartoMerge for the treatment of PAF. Methods Fifty-nine patients with PAF were enrolled in this study. Using Overlay Ref technique, a reference image (inverted) was faded into the live fluoroscopic image. Landmarks of CartoMerge were selected from anatomic points of the top of superior pulmonary veins (PVs) and the bottom of inferior PVs guided by Overlay Ref image. Overlay Ref images were also used to guide the ablation procedure combining with CartoMerge. Results All patients were successfully mapped by CartoMerge guided by Overlay Ref. The distance between the mapping points and the CT surfaces was (1.42±0.67) mm for the patients as a whole. This led to a successful rate of 96% for isolation of pulmonary veins. Duration of ablation procedure was (92±17) minutes. And the total duration of procedure was (139±32) minutes. CartoMerge could also be performed just with 3 paries to 4 paries selected landmarks guided by Overlay Ref without a full anatomic model constructed by Carto. Then, the total duration of procedure could be shortened to (115±38) minutes. Conclusions Overlay Ref technique can facilitate the catheter ablation of PAF and can help to standardize the procedure of landmarks selection.展开更多
基金supported by the National Key R&D Program of China(2019YFC1510700)the Sichuan Science and Technology Program(2023YFS0380, 2023YFS0377, 2019YFG0460, 2022YFS0539)。
文摘With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dangerous mountainous areas under the premise of ensuring the safety of personnel while restoring the real geographic information as much as possible. However, geological disaster areas are often accompanied by many adverse factors such as cliffs and dense vegetation. Based on this, the paper introduced the flight line design of oblique photogrammetry, analyzed the multi-platform data fusion processing, studied the multi-period data dynamic evaluation technology and proposed the application methods of data acquisition, early warning, disaster assessment and decision management suitable for geological disaster identification through the analysis of actual cases, which will help geologists to plan and control geological work more scientifically and rationally, improve work efficiency and reduce the potential personnel safety hazards in the process of geological survey, to offer technical support to the application of oblique photogrammetry in geological disaster identification and decision making and provide the scientific basis for personal and property safety protection and later-stage geological disaster management in disaster areas.
文摘This study is aimed to explore the clinical application of the guiding template designed by three-dimensional printing data for the insertion of sacroiliac screws.A retrospective study of 7 cases (from July 2016 to December 2016),in which the guiding template printed by the three-dimensional printing technique was used for the insertion of sacroiliac screws of patients with posterior ring injuries of pelvis,was performed.Totally,4 males and 3 females were included in template group,aged from 38to 65years old (mean 50.86±8.90).Of them,5 had sacral fractures (3 with Denis type Ⅰ and 2 with type Ⅱ)and 2 the separation of sacroiliac joint.Guiding templates were firstly made by the three-dimensional printing technique based on the pre-operative CT data. Surgical operations for the stabilization of pelvic ring by applying the guiding templates were carried out.A group of 8 patients with sacroiliac injuries treated by percutaneous sacroiliac screws were analyzed as a control group retrospectively.The time of each screw insertion,volume of intra-operative blood loss,and the exposure to X ray were analyzed and the Matta's radiological criteria were used to evaluate the reduction quality.The Majeed score was used to evaluate postoperative living quality.The visual analogue scale (VAS)was applied at different time points to judge pain relief of coccydynia.All the 7 patients in the template group were closely followed up radiographically and clinically for 14 to 20 months,mean (16.57±2.44)months.Totally 9 sacroiliac screws for the S 1 and S2 vertebra were inserted in the 7 patients.The time length for each screw insertion ranged from 450 to 870 s,mean (690.56±135.68)s,and the number of times of exposure to X ray were 4 to 8,mean (5.78±1.20).The intra-operative blood loss ranged from 45to 120 mL,mean (75±23.32)mL.According to Matta's radiology criteria,the fracture and dislocation reduction were excellent in 6cases and good in 1.The pre-operative VAS score ranged from 5.2 to 8.1,mean (7.13±1.00).The average one-week/six-month post-operative VAS was (5.33±0.78)and (1.33±0.66),respectively (P<0.05 when compared with pre-operative VAS).The 12-month post-operative Majeed score ranged from 86 to 92,mean (90.29±2.21).The three-dimensional printed guiding template for sacroiliac screw insertion,which could significantly shorten the operation time,provide a satisfied outcome of the stabilization of the pelvic ring,and protect doctors and patients from X-ray exposure,might be a practical and valuable new clinical technique.
基金This work was supported by the Brain Korea 2lProject and the Grallt of Post-Doc Program, KyungpookNational University (1999).
文摘Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.
文摘This study was carried out in the University of Campinas to study the three-dimensional reconstruction of grape bunches through the application of the Moire technique as an alternative and innovative method, using low-cost equipment for data acquisition. This study proposed the three-dimensional visualization of grapes and topography on Xi axes through the Moire projection technique. The artificial grapes with a 20 cm long bunch and 18.45 mm average diameter for each grape were used. A projector was used to generate a grid with light and dark lines. The grape bunch was placed on a holder, illuminated by a sinusoidal grid and photographed. After processing the images, a three-dimensional map of the fruit and topography on Xi axes were obtained. The three-dimensional fruit observation allows the visualization of the higher and lower regions of the three-dimensional configuration through a color map. This result makes it possible to obtain size and shape of the grape bunch, allowing for the process automation of product selection and classification.
基金This study was supported by the National key R&D plan(No.2020YFC2008100)the Science and Technology Innovation Team Project of the Shaanxi Innovation Capability Support Plan(No.S2020-ZC-TD-0029)the Science Foundation for Distinguished Young Scholars of Shaanxi Natural Science Basic Research Program(No.S2018-JC-JQ-0094)。
文摘Heart diseases remain the top threat to human health,and the treatment of heart diseases changes with each passing day.Convincing evidence shows that three-dimensional(3D)printing allows for a more precise understanding of the complex anatomy associated with various heart diseases.In addition,3D-printed models of cardiac diseases may serve as effective educational tools and for hands-on simulation of surgical interventions.We introduce examples of the clinical applications of different types of 3D printing based on specific cases and clinical application scenarios of 3D printing in treating heart diseases.We also discuss the limitations and clinically unmet needs of 3D printing in this context.
基金supported by grants from the National Key Research and Development Plan of China,No.31670986(to QTZ)the Science and Technology Project of Guangdong Province of China,No.2014B020227001,2017A050501017(to QTZ)the Science and Technology Project of Guangzhou of China,No.201807010082(to QTZ),201704030041(to JQ)
文摘The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging(Micro-MRI), an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions(Mannerist Solution/GD-DTPA contrast agent, distilled water) were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent(Mannerist Solution/GD-DTPA) and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.
基金the Fundamental Research Funds for the Provincial Universities,China(No.702/000007020303)。
文摘A new collapse model of the trapdoors,three-dimensional rectangular trapdoor(3DRT),is presented for ground surface collapse.Undrained stability of 3DRT is examined with the upper bound method of plasticity limit analysis theory.The soil where the trapdoors are located is assumed to be a perfectly plastic model with a Tresca yield criterion.Block analysis technique is employed to investigate the collapse of 3DRT.The model is divided into five different block types and added up to ten rigid blocks.According to the law of conservation of energy,the critical stability ratios of 3DRT are obtained through a search proceeding.The results of upper bound solution for 3DRT are given,and three trapdoor models with depth various are discussed during the application in the stability analysis of square trapdoors.The critical stability ratios can be used in the design of underground excavation and support force.
基金supported by a grant from the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Fluoro-ruby was injected into the posterior funiculus of the spinal cord in the cervical (C5-T2) and lumbar (L3-6) segments of adult guinea pigs. The spinal cord was cut into serial frozen sections. The Fluoro-ruby labeling was clearly delineated from the surrounding structure. The labeling traversed the cervical, thoracic and lumbar segments, and was located on the ventral portion of the posterior funiculus on the injected side, proximal to the intermediate zone of the dorsal gray matter. The fluorescence area narrowed rostro-caudally. The spinal cord, spinal cord gray matter and corticospinal tract were reconstructed using 3D-DOCTOR 4.0 software, resulting in a robust three-dimensional profile. Using functionality provided by the reconstruction software, free multi-angle observation and sectioning could be conducted on the spinal cord and corticospinal tract. Our experimental findings indicate that the Fluoro-ruby retrograde fluorescent tracing technique can accurately display the anatomical location of corticospinal tract in the guinea pig and that three-dimensional reconstruction software can be used to provide a three-dimensional image of the corticospinal tract.
基金This project was financially supported by the National Committee of Science and Technology Grants/903-85-08-05
文摘A three-dimensional, first order turbulence closure, thermal diffusion model is described in this paper. The governing equations consist of an equation of continuity, three components of momentum, conservation equations for salt, temperature and subgridscale energy, and an equation of state. In the model, according to the hypothesis of Kolmogorov and Prandtl, the viscosity coefficient of turbulent flow of homogeneous fluid is related to the local turbulent energy, and the horizontal and vertical exchange coefficients of mass, heat and momentum are computed with the introduction of subgridscale turbulence energy. The governing equations are solved by finite difference techniques. This model is applied to the Jiaozhou bay to predict thermal pollution by the Huangdao power plant. An instantaneous tidal current field is computed, then the distribution of temperature increment is predicted, and finally the effect of wind stress on thermal discharge is discussed.
文摘The surgical removal of renal cancer,along with the thrombectomy of the inferior vena cava tumour thrombus,represents a remarkable milestone in urological surgery.This procedure is not only technically demanding but also requires a high level of surgical expertise.Managing renal cancer combined with a vena cava tumour thrombus poses significant challenges,especially when dealing with combined grade Ⅱ-Ⅳ inferior vena cava tumour thrombus.The complexity of these cases is further exacerbated by the delicate anatomical structures involved and the need to preserve critical vessels while effectively removing the tumour.The Upper Urethral Tumour Treatment Centre of Weifang People's Hospital successfully treated a challenging case of left renal tumour combined with grade II inferior vena cava tumour thrombus.The surgical team,led by experienced urological surgeons,meticulously planned and executed the procedure,ensuring minimal trauma to the patient and complete removal of the tumour.This achievement not only demonstrates the hospital's commitment to providing state-of-the-art surgical care but also highlights the importance of continued research and training in urological oncology.The successful outcome of this case is a testament to the expertise and dedication of the medical team and offers hope to patients facing similar complex surgical challenges.
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.
文摘Fenlong green ecological agriculture technology (Fenlong technology), a new smash ridging farming method developed by Guangxi Academy of Agdcultural Sciences, has been elected as the recommended cultivation technique by the Ministry of Agriculture of China. It replaces the traditional plowshare with spiral drill, and its tilth depth is twice deeper than that by tractor tilthing. It also extends soil nutrient, moisture, oxygen and microorganism, the so-called "Four pools". Soil nutrient, oxygen, microorganism, light and rainfall use ratio is increased by 10%-100%, creating a platform for natural increase of more than 10% of crop yield. Its application to over 20 kinds of crops in 21 provinces has proved that the yield increases 10-30% with quality enhancing 5% and double water retaining capacity but no more input. When the application area of Fenlong could reach 67 million hm2, the amount of fertilizer can be reduced by 40-50 billion kg, saving 120-150 billion Yuan. In this paper, we put forward the strategy of "4+1" (arable, saline-alkali soil, grasslands, Sponge City + rivers) green development in China, and deepened the Fenlong cultivated tilled layer from 16.5 cm to 35 cm for 67 million hm2 arable land, ridged 13.3 million hm2 of saline-alkali soil for 35 cm, and also 35 cm for 67 million hm2 degraded steppe, which could have the following 3 effects: first, the 147 million hm2 of land with Fenlong cultivation could increase loosing soil to 315.491 billion m3, in* creasing by 159.26% for 120 million hm2 of arable land with the average tilled layer of 16.5 cm, which has loosing soil of only 198.1 billion m3, that is, the space of the land increases 1.6 times. Second, every hectare of plowland could store up to 450 m3/hm2 of natural rainfall, and the unused 60 m3 of saline-alkali soil and grasslands could store water of 102 billion m3, showing an increase of over 88.89% for the current plowland storage of 54 billion m3 at now, that is, double the natural rainfall storage capacity. Third, the two multiple increase of natural resources application can bring trillions of resource activation, environmental cleaning, food security, citizens, health, economic, ecological and social benefits, and makes the Chinese nation move forward in green development. Its application in "big scientific research" and "One Belt And One Road" will contribute Chinese strength to the world.
文摘Objective:This study investigated the effect of proximal contact strength on the three-dimensional displacements of cantilever fixed partial denture(CFPD) under vertically concentrated loading with digital laser speckle(DLS) technique.Methods:Fresh mandible of beagle dog was used to establish the implant-supported CFPD for specimen.DLS technique was employed for measuring the three-dimensional displacement of the prosthesis under vertically concentrated loading ranging from 200 to 3 000 g.The effect of the contact tightness on the displacement of CFPD was investigated by means of changing the contact tightness.Results:When an axial concentrated loading was exerted on the pontic of the implant-supported CFPD,the displacement of the CFPD was the greatest.The displacement of the prosthesis decreased with the increase of contact strength.When the contact strength was 0,0.95,and 3.25 N,the displacement of the buccolingual direction was smaller than that of the mesiodistal direction but greater than that of the occlusogingival direction.When the force on the contact area was 6.50 N,the mesiodistal displacement of the prosthesis was the biggest while the buccolingual displacement was the smallest.Conclusions:The implant supported CFPD is an effective therapy for fully or partially edentulous patients.The restoration of the contact area and the selection of the appropriate contact strength can reduce the displacement of the CFPD,and get a better stress distribution.The most appropriate force value is 3.25 N in this study.
文摘Background:Radiological imaging plays a pivotal role in forensic anthropology.As have the imaging techniques advances,so have the digital skeletal measurements inched towards precision.Secular trends of the population keep on changing in modem times.Hence,finding the precise technique of bone measurement,with greater reproducibility,in modem population is always needed in making population specific biological profile.Aim and Objective:The aim of this study was to estimate the accuracy of the foramen magnum measurement,obtained by three dimensional multi-detector computed tomography using volume rendering technique with the cut off value of each variable,in sex determination of an individual.Materials and Methods:Two metric traits,an antero-posterior diameter(APD)and transverse diameter(TD),were measured digitally in an analysis of 130 radiological images having equal proportion of male and female samples.Foramen magnum index and area of foramen magnum(Area by Radinsky's[AR],Area by Teixeira5s[AT])were derived from APD and TD.Results:Descriptive statistical analysis,using unpaired t-test,showed significant higher value in males in all the variables.Using Pearson correlation analysis,maximum correlation was observed between area(AT and AR r=0.999)and between area and TD(AR r=0.955 and AT r=0.945 respectively).When used individually,TD had the highest predictive value(67.7%)for sex detennination among all the parameters followed by AT(65.4%)and AR(64.6%).Cutoff value of variables TD,AR and AT were 29.9 mm,841.80 mm2 and 849.70 mm2 respectively.Receiver operating characteristic curve predicted male and female sex with 96.2%and 89.2%accuracy respectively.The overall accuracy of the model was 92.7%.Conclusion:Measurements from 3D CT using volume rendering technique were precise,and the application of logistic regression analysis predicted the sex with more accuracy.
文摘Developments of digital technology and three-dimensional(3D)reconstruction allowed a precise description of anatomic structures.With the introduction of Visible Human Project and Virtual Chinese Human(VCH)techniques,more detailed anatomic images could be obtained.Digitized visible models of these structures can be applied as a useful tool in clinical training.The aim of this study was to reconstruct the normal structures of thoracodorsal artery in 3D images and to establish the digitized visible models of latissimus dorsi myocutaneous(LDM)flap.The cross-sectional images from the four VCH datasets were reviewed to study LDM and thoraco-dorsal artery structures on a section-by-section basis.Next,two adult fresh cadaver specimens were perfused with lead oxide-gelatine mixture and subject to radio-graphic CT scanning on their torsos.The cross-sectional images from the CT images were reviewed to study thor-acodorsal artery structures.Three-dimensional computer-ized reconstructions of LDM flap structures were conducted from these datasets by using Amira 3.1(TGS)software respectively.The 3D reconstructed visible models established from these datasets perfectly displayed the anatomic characteristics of LDM flap.
文摘Objectives This study was to investigate the differences between modeling and non-modeling left atrium (LA) in CartoXP system guided catheter ablation for paroxysmal atrial fibrillation (PAF). Methods From Jan to Dec in 2008 total 31 cases with PAF were enrolled. All were treated by the same electrophysiologist with CartoXP guidance. Catheter ablation was accomplished without left atrium and pulmonary veins modeling in 17 patients (non-modeling group) and with left atrium modeling in 14 patients (modeling group). The detailed ablation method was based on circumferential pulmonary veins isolation (CPVI). And linear ablation of tricuspid valvular isthmus was performed individually. The ablation endpoint was a complete isolation of pulmonary vein potential from left atrium and no further induced continuous fast atrial arrhythmia including atrial fibrillation (AF), atrial flutter (AFL) and atrial tachycardia (AT). Each step for the procedures and the follow-up outcomes were compared correspondingly. Results The total procedure time was 107.23 ± 28.92 min in modeling group vs 93.47 ±26.09 min in non-modeling group ( P 〉 0.05 ). The X-ray exposure time was significantly longer in modeling group (21.09 ±6. 49 rain) than in non-modeling group (14. 16 ± 5.35 min). The CPVI times of right pulmonary veins and left pulmonary veins were 28. 14 ± 9. 26 min was 27.29 ± 18.53 min in modeling group respectively, vs 18.00 ±4. 51 min and 23.94 ± 7. 10 min in non-modeling group respectively, (P 〈 0. 05 ). There is no significant difference between modeling group (85.7%) and non-modeling group (82.4%) over follow-up period of 2 to 13 months. Confusions CartoXP system guided catheter ablation of PAF without modeling of left atrium and pulmonary veins took less time in X-ray exposure and ablation steps, comparing with left atrium modeling procedure.
文摘According to the question of how to transfer data between Pro/E and ADAMS correctly, the paper gives an improved importing solution, which combines the interface and the Standard Data Format(SDF) files. It settles the problems caused by improper geometry during the import conducted by the interface software. With the solution ,fea- ture points can be conveniently picked to build kinematic constraints are the preparation of the model will be simpli- fied. An example is given for the method, and corresponding simulations are conducted. The results of the simula- tions verify the validity of the solution.
基金Acknowledgements This work was supported by the Foundation of State Key Laboratory of Pollution Control and Resource Reuse (Tongji University), China (No. PCRRE16019), the National Natural Science Foundation of China (Grant Nos. 51678422 and 51378368), Sheng Yun- Fei College Students Scientific and Technological Innovation Fund, China Scholarship Council (No. 201506260022), the National Science & Technology Pillar Program (No. 2013BAD21B03), and the higher school innovative engineering plan (111 Projec0.
文摘The quantification and effects of system pH value on the interactions between Pb(II) and the biopolymer in activated sludge were investigated. The biopolymer had two protein-like fluorescence peaks (Ex/Em = 280 nm1326-338 nm for peak A; Ex/Em = 220-230 nm/324-338 nm for peak B). The fluorescence intensities of peak B were higher than those of peak A. The fluorophores of both peaks could be largely quenched by Pb(ll), and the quencher dose for peak B was about half of that for peak A. The modified Stern-Volmer equation well depicted the fluorescence quenching titration. The quenching constant (Ka) values for both peaks decreased with rising system pH value, and then sharply decreased under alkaline conditions. It could be attributed to that the alkaline conditions caused the reduction of available Pb(II) due to the occurrence of Pb(OH)2 sediments. The Ka values of peak B were bigger than those for peak A at the same system pH values. Accordingly, the aromatic proteins (peak B) played a key role in the interactions between metal ions and the biopolymer.
文摘Background CartoMerge has been widely used in guiding circumferential pulmonary vein isolation (CPVI) for the treatment of paroxysmal atrial fibrillation (PAF). However, the procedure of landmarks selection varies among operators according to their experience. Techniques have to be established to standardize this procedure. We propose that Overlay Ref could facilitate this procedure. This paper aimed to report our initial experience with CPVI guided by Overlay Ref and CartoMerge for the treatment of PAF. Methods Fifty-nine patients with PAF were enrolled in this study. Using Overlay Ref technique, a reference image (inverted) was faded into the live fluoroscopic image. Landmarks of CartoMerge were selected from anatomic points of the top of superior pulmonary veins (PVs) and the bottom of inferior PVs guided by Overlay Ref image. Overlay Ref images were also used to guide the ablation procedure combining with CartoMerge. Results All patients were successfully mapped by CartoMerge guided by Overlay Ref. The distance between the mapping points and the CT surfaces was (1.42±0.67) mm for the patients as a whole. This led to a successful rate of 96% for isolation of pulmonary veins. Duration of ablation procedure was (92±17) minutes. And the total duration of procedure was (139±32) minutes. CartoMerge could also be performed just with 3 paries to 4 paries selected landmarks guided by Overlay Ref without a full anatomic model constructed by Carto. Then, the total duration of procedure could be shortened to (115±38) minutes. Conclusions Overlay Ref technique can facilitate the catheter ablation of PAF and can help to standardize the procedure of landmarks selection.