期刊文献+
共找到3,024篇文章
< 1 2 152 >
每页显示 20 50 100
Digital reconstruction of three-dimensional contours and its application to microstructural evaluation of postblast rock fissure surfaces
1
作者 Yanbing Wang Zhaoyang Wang +1 位作者 Dairui Fu Mingwei Gang 《Deep Underground Science and Engineering》 2025年第2期316-328,共13页
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
关键词 cube covering method evaluation of damage characterization fractal dimension roughness three-dimensional contour scanning
原文传递
Ecological Three-Dimensional Cultivation and Digital Development Model of Xinjiashan Specialty Coffee Base
2
作者 Jiangnan WANG Yulian MA +3 位作者 Tingting YANG Caide DUAN Jin'e LI Guangxue YANG 《Plant Diseases and Pests》 2026年第1期22-25,29,共5页
Under the strategic framework of rural revitalization and agricultural modernization, Xinjiashan Specialty Coffee Base, located in Zaotang Village, Lujiang Town, Longyang District, Baoshan City, has been proactively i... Under the strategic framework of rural revitalization and agricultural modernization, Xinjiashan Specialty Coffee Base, located in Zaotang Village, Lujiang Town, Longyang District, Baoshan City, has been proactively investigating innovative models for agricultural development. Through extensive communication and collaboration, this base has established close partnerships with research institutions including Kunming University of Science and Technology, Baoshan University, and Yunnan Academy of Agricultural Sciences, with a commitment to thoroughly exploring the potential for resource recycling and ecological complementarity. An innovative four-in-one three-dimensional integrated planting system incorporating "coffee, bananas, green manure, and bees" has been implemented. Concurrently, technological and digital management strategies have been comprehensively integrated to improve planting efficiency. Under this model, the proportion of specialty coffee attains 71%, and the per-unit yield is 17% greater than that of the conventional planting model. This approach not only substantially enhances economic returns but also promotes the integrated development of ecological and social benefits, offering a valuable practical example and experiential reference for the specialty and sustainable advancement of the coffee industry in comparable regions. 展开更多
关键词 COFFEE three-dimensional planting digitalIZATION Ecological cycle Xinjiashan
在线阅读 下载PDF
Evaluation of Maxillary Dental Arch Widths in Individuals Having Unilateral and Bilateral Cleft Lip and Palate Using Three-Dimensional Digital Models
3
作者 Ege Dogan Abdü +2 位作者 lkadir Iş ik Servet Dogan 《Open Journal of Stomatology》 2019年第7期159-167,共9页
Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had ... Aim: Maxillary dental arch widths were evaluated in individuals having unilateral (UCLP) and bilateral (BCLP) cleft lip and palate (CLP) using three-dimensional (3D) digital models. Material and Method: The study had been conducted on 80 individuals aged between 14 - 17 years having UCLP and BCLP. 40 of the individuals had UCLP, whereas 40 had BCLP. The maxillary dental models taken from patients before the treatment were scanned using Orthomodel Programme (v.1.01, Orthomodel Inc., Istanbul, Turkey) to obtain 3D imagery. Student’s t-test was used in order to assess the data obtained by using SPSS software version 22.0. Results: In BCLP, the average inter-canine distance was 17.44 ± 1.31 mm, the average inter-molar distance was 36.57 ± 1.12 mm, while inter-canine/inter-molar ratio was 0.47. Whereas in UCLP, it was 25.10 ± 0.63 mm, 42.20 ± 0.53 mm and 0.59. The inter-canine distance in UCLP was found to be large enough to be statistically significant (p 0.05), even though there were differences in inter-molar widths. Conclusion: For the stable orthodontic treatment results, one of the most important points is arch form and widths to be coherent with each other. In our study, the increase of inter-canine distance seen in UCLP indicates that in the cleft region, the maxillary arch is inclined over to the back, while the same situation in BCLP suggests that the maxillary segments are collapsed inside. The difference in the arch is highly affected by the primary surgical treatment. 展开更多
关键词 UNILATERAL CLEFT LIP and PALATE Bilateral CLEFT LIP and PALATE three-dimensional digital Models
暂未订购
Construction of Vocational Education Quality Evaluation Index System from the Perspective of Digital Transformation Based on the Analytic Hierarchy Process of Higher Vocational Colleges in Hainan Province,China 被引量:2
4
作者 Limei Fu 《Journal of Contemporary Educational Research》 2025年第1期282-289,共8页
In the context of the digital transformation of vocational education,a quality evaluation index system has been constructed.Based on a questionnaire survey conducted among higher vocational colleges and enterprises in... In the context of the digital transformation of vocational education,a quality evaluation index system has been constructed.Based on a questionnaire survey conducted among higher vocational colleges and enterprises in Hainan Province,it has been found that the quality of vocational education generally depends on the talent training program and professional construction at the macro level.At the meso level,the teacher level and teaching environment are critical,while at the micro level,the evaluation of talent training quality cannot be underestimated.Strategies for quality improvement in vocational education are proposed from the perspectives of talent training programs,major construction,teacher development,teaching environment,and talent training quality,all under the lens of digital transformation. 展开更多
关键词 digital transformation Vocational education evaluation index system
在线阅读 下载PDF
Digital twin-based resilience evaluation and intelligent strategies of smart urban water distribution networks for emergency management 被引量:2
5
作者 Hongyan Dui Taiyu Cao Fan Wang 《Resilient Cities and Structures》 2025年第1期41-52,共12页
Resilient smart urban water distribution networks are essential to ensure smooth urban operation and maintain daily water services.However,the dynamics and complexity of smart water distribution networks make its re-s... Resilient smart urban water distribution networks are essential to ensure smooth urban operation and maintain daily water services.However,the dynamics and complexity of smart water distribution networks make its re-silience study face many challenges.The introduction of digital twin technology provides an innovative solution for the resilience study of smart water distribution networks,which can more effectively support the network’s real-time monitoring and intelligent control.This paper proposes a digital twin architecture of smart water dis-tribution networks,laying the foundation for the resilience assessment of water distribution networks.Based on this,a performance evaluation model based on user satisfaction is proposed,which can more intuitively and effectively reflect the performance of urban water supply services.Meanwhile,we propose a method to quantify the importance of water distribution pipes’residual resilience,considering the time value to optimize the re-covery sequence of failed pipes and develop targeted preventive maintenance strategies.Finally,to validate the effectiveness of the proposed method,this paper applies it to a water distribution network.The results show that the proposed method can significantly improve the resilience and enhance the overall resilience of smart urban water distribution networks. 展开更多
关键词 digital twin Smart water distribution network Resilience evaluation Importance measure
在线阅读 下载PDF
Construction and Empirical Study of a Digital Evaluation Model for Classroom Teaching Quality in Private Colleges and Universities:A Case Study of Landscape Architecture Major at Chongqing University of Humanities,Science and Technology
6
作者 LI Guoqing DU Kaiwei +1 位作者 XU Yunfeng TANG Min 《Journal of Landscape Research》 2025年第5期65-70,74,共7页
Focusing on the digital evaluation of classroom teaching quality in private colleges and universities,an indicator model of“teaching subject-teaching object-teaching effect”for the landscape architecture major of Ch... Focusing on the digital evaluation of classroom teaching quality in private colleges and universities,an indicator model of“teaching subject-teaching object-teaching effect”for the landscape architecture major of Chongqing College of Humanities,Science&Technology was constructed.By using methods such as Delphi,AHP,Likert and questionnaire survey,the teaching quality of 8 courses of landscape architecture major was evaluated.The results show that the average score of the indicators is 2.8776,indicating that the overall improvement space for the teaching quality of the sample professional courses is relatively large,and the key shortcomings are students’learning interest and initiative,the application and transformation of professional knowledge,as well as the cultivation of innovation and practical ability.The research verified the scientific nature and discrimination of the model,and put forward suggestions for the precise improvement of classroom atmosphere,assignment design and ability cultivation driven by data,thereby providing a replicable model for the digital evaluation and teaching quality improvement of engineering majors in private colleges and universities. 展开更多
关键词 digital evaluation Teaching quality Landscape architecture
在线阅读 下载PDF
Droplet Digital PCR for Diagnosing Brucellosis Spondylitis:Method Development and Evaluation
7
作者 Xiuqin Chang Guangtian Liu +3 位作者 Bo Li Meng Hao Xuefeng Jiang Zhiguo Liu 《Biomedical and Environmental Sciences》 2025年第7期877-880,共4页
Brucellosis is a global public health issue that severely affects human health,Brucella melitensis is currently the predominant species in China.Brucella spondylitis is the primary cause of the debilitating and disabl... Brucellosis is a global public health issue that severely affects human health,Brucella melitensis is currently the predominant species in China.Brucella spondylitis is the primary cause of the debilitating and disabling complications[1].The lumbar vertebra was the most commonly affected site,followed by the thoracic,cervical,thoracolumbar,and lumbosacral segments,and back pain,fever,sweating,and fatigue were the most common symptoms[2].However,the diagnosis of Brucella spondylitis is challenging owing to its wide spectrum of clinical presentations,cross-reactions with other bacteria,and low strain isolation rate.Therefore,a timely and accurate diagnosis of spinal brucellosis is crucial for implementing an effective therapeutic plan and improving treatment outcomes.Droplet digital polymerase chain reaction(ddPCR)is widely used for low-abundance nucleic acid detection and is useful for diagnosing infectious diseases[3].Therefore,this study aimed to evaluate the ddPCR approach for the diagnosis of brucellosis with spondylitis to improve its clinical diagnostic capacity. 展开更多
关键词 Droplet digital PCR Clinical Presentation Method Development lumbar vertebra Public Health Issue Diagnostic evaluation Brucella Melitensis brucella spondylitis
暂未订购
Digital Evaluation of Sitting Posture Comfort in Human-vehicle System under Industry 4.0 Framework 被引量:9
8
作者 TAO Qing KANG Jinsheng +2 位作者 SUN Wenlei LI Zhaobo HUO Xiao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第6期1096-1103,共8页
Most of the previous studies on the vibration ride comfort of the human-vehicle system were focused only on one or two aspects of the investigation. A hybrid approach which integrates all kinds of investigation method... Most of the previous studies on the vibration ride comfort of the human-vehicle system were focused only on one or two aspects of the investigation. A hybrid approach which integrates all kinds of investigation methods in real environment and virtual environment is described. The real experimental environment includes the WBV(whole body vibration) test, questionnaires for human subjective sensation and motion capture. The virtual experimental environment includes the theoretical calculation on simplified 5-DOF human body vibration model, the vibration simulation and analysis within ADAMS/VibrationTM module, and the digital human biomechanics and occupational health analysis in Jack software. While the real experimental environment provides realistic and accurate test results, it also serves as core and validation for the virtual experimental environment. The virtual experimental environment takes full advantages of current available vibration simulation and digital human modelling software, and makes it possible to evaluate the sitting posture comfort in a human-vehicle system with various human anthropometric parameters. How this digital evaluation system for car seat comfort design is fitted in the Industry 4.0 framework is also proposed. 展开更多
关键词 sitting posture comfort human-vehicle system digital design digital evaluation Industry 4.0
在线阅读 下载PDF
DAMAGE AND FRACTURE EVALUATION OF GRANULAR COMPOSITE MATERIALS BY DIGITAL IMAGE CORRELATION METHOD 被引量:3
9
作者 张珏 熊春阳 +3 位作者 李宏举 李明 王建祥 方竞 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2004年第4期408-417,共10页
This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of some granular based composite materials including steel- fiber reinforced concrete,sandstone a... This paper presents the applications of digital image correlation technique to the mesoscopic damage and fracture study of some granular based composite materials including steel- fiber reinforced concrete,sandstone and crystal-polymer composite.The deformation fields of the composite materials resulted from stress localization were obtained by the correlation computation of the surface images with loading steps and thus the related damage prediction and fracture parameters were evaluated.The correlation searching could be performed either directly based on the gray levels of the digital images or from the wavelet transform(WT)coefficients of the transform spectrum.The latter was developed by the authors and showed higher resolution and sensitivity to the singularity detection. Because the displacement components came from the rough surfaces of the composite materials without any coats of gratings or fringes of optical interferometry,both surface profiles and the deformation fields of the composites were visualized which was helpful to compare each other to analyze the damage of those heterogeneous materials. 展开更多
关键词 digital image correlation deformation field evaluation granular based composites damage and fracture
在线阅读 下载PDF
Three-dimensional visualization interactive system for digital twin workshop 被引量:8
10
作者 Zhang Qinglei Yang Zhiwei +2 位作者 Duan Jianguo Liu Zhen Qin Jiyun 《Journal of Southeast University(English Edition)》 EI CAS 2021年第2期137-152,共16页
To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of th... To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of the 3D visualization interactive system for digital twin workshops is proposed.As the traditional 5D digital twin model ignores the importance of human-computer interaction,a new dimension of the user terminal was added.A hierarchical real-time data-driven mapping model for the workshop production process is then proposed.Moreover,a real-time data acquisition method for the industrial Internet of things is proposed based on OPC UA(object linking and embedding for process control unified architecture).Based on the 6D model of the system,the process of creating a 3D visualization virtual environment based on virtual reality is introduced,in addition to a data-driven process based on the data management cloud platform.Finally,the 6D model of the system was confirmed using the blade rotor test workshop as the object,and a 3D visualization interactive system is developed.The results show that the system is more transparent,real-time,data-driven and more efficient,as well as promotes the coordination and integration of human-physical-virtual,which has practical significance for developing digital twin workshops. 展开更多
关键词 digital twin workshop three-dimensional visualization human-computer interaction data driven OPC UA(object linking and embedding for process control unified architecture)
在线阅读 下载PDF
Optical encryption of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography 被引量:2
11
作者 Ying Wang Qi Liu +1 位作者 Jun Wang Qiong-Hua Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第3期253-259,共7页
We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the ... We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance. 展开更多
关键词 multiple three-dimensional objects encryption single-pixel digital holography phase-shifting in- terference compressive sensing
原文传递
A combination of digital design and three-dimensional printing to assist treatment of thoracolumbar compression fractures using percutaneous kyphoplasty 被引量:2
12
作者 Hui Lu Daixiang Jiang +1 位作者 Qimei Wu Rong Liu 《Global Health Journal》 2021年第4期190-193,共4页
Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tur... Objective:To evaluate the clinical efficacy of the preoperative digita1 design combined with three dimensional(3D)printing models to assist percutaneous kyphoplasty(PKP)treatment for thoracolumbar compression frac tures.Methods:From January 2018 to August 2020,we obtained data of 99 patients diagnosed thoracolumbar compression fractures.These patients were divided into control group(n=50)underwent traditional PKP surgery,and observation group(n=49)underwent preoperative digital design combined with 3D printing model assisted PKP treatment.The clinical efficacy was evaluated with five parameters,including operation time,number of intraoperative radiographs,visual analogue scale(VAS)score,Cobb Angle change,and high compression rate of injured vertebrae.Results:There were statistically significant differences of operation time and number of intraoperative radio graphs between the two groups(P<0.05).For VAS score,Cobb Angle change and vertebral height compression rate,all of these three parameters were significantly improved when the patients accepted surgery teatment in two groups(P<0.05).However,there were no significant differences between control group and observation group for these three parameters either before or after surgery(P>0.05).Conclusions:Through the design of preoperative surgical guide plate and the application of 3D printing model to guide the operation,the precise design of preoperative surgical puncture site and puncture Angle of the injured vertebra was realized,the number of intraoperative radiographs was reduced,the operation time was shortened and the operation efficiency was improved. 展开更多
关键词 Percutaneous kyphoplasty Thoracolumbar compression fracture digital design three-dimensional(3D)printing
暂未订购
Method for evaluation of geological strength index of carbonate cliff rocks:Coupled hyperspectral-digital borehole image technique 被引量:1
13
作者 Haiqing Yang Guizhong Huang +3 位作者 Chiwei Chen Yong Yang Qi Wang Xionghui Dai 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4204-4215,共12页
The deterioration of unstable rock mass raised interest in evaluating rock mass quality.However,the traditional evaluation method for the geological strength index(GSI)primarily emphasizes the rock structure and chara... The deterioration of unstable rock mass raised interest in evaluating rock mass quality.However,the traditional evaluation method for the geological strength index(GSI)primarily emphasizes the rock structure and characteristics of discontinuities.It ignores the influence of mineral composition and shows a deficiency in assessing the integrity coefficient.In this context,hyperspectral imaging and digital panoramic borehole camera technologies are applied to analyze the mineral content and integrity of rock mass.Based on the carbonate mineral content and fissure area ratio,the strength reduction factor and integrity coefficient are calculated to improve the GSI evaluation method.According to the results of mineral classification and fissure identification,the strength reduction factor and integrity coefficient increase with the depth of rock mass.The rock mass GSI calculated by the improved method is mainly concentrated between 40 and 60,which is close to the calculation results of the traditional method.The GSI error rates obtained by the two methods are mostly less than 10%,indicating the rationality of the hyperspectral-digital borehole image coupled evaluation method.Moreover,the sensitivity of the fissure area ratio(Sr)to GSI is greater than that of the strength reduction factor(a),which means the proposed GSI is suitable for rocks with significant fissure development.The improved method reduces the influence of subjective factors and provides a reliable index for the deterioration evaluation of rock mass. 展开更多
关键词 Hyperspectral image digital panoramic borehole image Geological strength index Carbonate rock mass Quantitative evaluation
在线阅读 下载PDF
Differentiated digital library evaluation in a hierarchical model stemming from its operational scope and complexity 被引量:2
14
作者 WU Jianhua WANG Zhaohui 《Chinese Journal of Library and Information Science》 2009年第4期54-70,共17页
Digital libraries are complex systems and this brings difficulties for their evaluation. This paper proposes a hierarchical model to solve this problem, and puts the entangled matters into a clear-layered structure. F... Digital libraries are complex systems and this brings difficulties for their evaluation. This paper proposes a hierarchical model to solve this problem, and puts the entangled matters into a clear-layered structure. Firstly, digital libraries(DLs thereafter)are classified into 5 groups in ascending gradations, i.e. mini DLs, small DLs, medium DLs,large DLs, and huge DLs by their scope of operation. Then, according to the characteristics of DLs at different operational scope and level of sophistication, they are further grouped into unitary DLs, union DLs and hybrid DLs accordingly. Based on this simulated structure,a hierarchical model for digital library evaluation is introduced, which evaluates DLs differentiatingly within a hierarchical scheme by using varying criteria based on their specific level of operational complexity such as at the micro-level, medium-level, and/or at the macro-level. Based on our careful examination and analysis of the current literature about DL evaluation system, an experiment is conducted by using the DL evaluation model along with its criteria for unitary DLs at micro-level. The main contents resulting from this evaluation experimentation and also those evaluation indicators and relevant issues of major concerns for DLs at medium-level and macro-level are also to be presented at some length. 展开更多
关键词 digital libraries evaluation Hierarchical model Unitary digital library Union digital library Hybrid digital library
原文传递
The Application of Digital Optical 3D Image Analyzer Evaskin in The Evaluation of Wrinkles 被引量:1
15
作者 Wang Xingkai Liu Hui +3 位作者 Liu Fei Chen Bowen Wu Tao Yang Suzhen 《China Detergent & Cosmetics》 CAS 2024年第3期62-66,共5页
To verify the effectiveness of digital optical 3D image analyzer EvaSKIN in the objective and quantitative evaluation of wrinkles.A total of 115 subjects were recruited,the facial images of the subjects were collected... To verify the effectiveness of digital optical 3D image analyzer EvaSKIN in the objective and quantitative evaluation of wrinkles.A total of 115 subjects were recruited,the facial images of the subjects were collected by digital optical 3D image analyzer and manual camera,the changes of crow’s feet with age were analyzed.Pictures obtained by manual photography can be directly used for observation and preliminary grading of wrinkles.However,the requirements for evaluators are high,and the results are prone to errors,which will affect the accuracy of the evaluation.Therefore,skilled raters are needed.Compared with the manual photography method,the digital optical 3D image analyzer EvaSKIN can realize three-dimensional extraction of wrinkles,and obtain the change trend of crow’s feet with age.20~30 years old,wrinkles begin to appear slowly;wrinkles will increase rapidly at the age of 30~50;The length of 50~60 year old wrinkles is basically fixed,the wrinkles develop longitudewise,gradually widen and deepen,and the area,depth and volume increase is obvious,and the skin aging condition is intensified.the digital optical 3D image analyzer EvaSKIN realizes the 3D extraction of wrinkles,quantifies the circumference,area,average depth,maximum depth and volume of wrinkles,realizes the objective and quantitative evaluation of wrinkle state,is more accurate in the measurement of wrinkles,and provides a new instrument and method for the evaluation of wrinkles.it is a perfect and supplement to the traditional evaluation methods,and to a certain extent,it helps the research and development and evaluation institutions of cosmetics to obtain more abundant and three-dimensional data support. 展开更多
关键词 digital optical 3D image analyzer EvaSKIN skin wrinkles age quantitative evaluation
在线阅读 下载PDF
Rapid digitalization and panoramic evaluation of weld X-ray film
16
作者 闫志鸿 宋永伦 +1 位作者 王彬 李元香 《China Welding》 EI CAS 2011年第1期49-53,共5页
The computer evaluation of weld X-ray film is an attractive technique for weld seam NDT ( nondestructive testing). To achieve this target, digitalization of film is the first step and automatic defect identification... The computer evaluation of weld X-ray film is an attractive technique for weld seam NDT ( nondestructive testing). To achieve this target, digitalization of film is the first step and automatic defect identification is another key technique. In this paper, a weld X-ray film digitalizing system has been established with linear array CCD and highlight LED light source. Its space resolution can reach 0. 04 mm/pixel and scanning speed can reach 100 mm/s for an industrial film. The transfer function curves of the system have been measured and the results indicate that its image gray resolution can reach 88 G/D at 4. 5D, and its dynamic range can be wider than 2. OD. In order to facilitate the evaluation of large welded structure, a panoramic evaluation algorithm is developed also. The algorithm includes image matching, image fusion and panoramic evaluation of the long linked film image. 展开更多
关键词 weld X-ray film rapid digitalization image processing panoramic evaluation
在线阅读 下载PDF
Evaluation of corticospinal tract injury with three-dimensional diffusion tensor tract in patients with acute cerebral infarction
17
作者 Hui Xiao Ziqian Chen +1 位作者 Biyun Zhang Ping Ni 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第8期725-728,共4页
BACKGROUND:Three-dimensional diffusion tensor tract(DTT)is the newest imaging to describe the structure of white matter fiber in three-dimensions,it has great significance in dividing the concrete anatomic site of gra... BACKGROUND:Three-dimensional diffusion tensor tract(DTT)is the newest imaging to describe the structure of white matter fiber in three-dimensions,it has great significance in dividing the concrete anatomic site of gray and white matter lesions,displaying the correlation with fibrous band and judging clinical prognosis,which is incomparable by other imagings.OBJECTIVE:To observe the conditions of corticospinal tract(CST)in acute cerebral ischemic stroke patients,and analyze the relationship between motor function and the severity of CST injury.DESIGN:A case-control observation.SETTING:Department of Medical Imaging,Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA.PARTICIPANTS:Fifteen patients with acute cerebral infarction were selected from Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA from February to December in 2005.They all suffered from acute attack and motor disorder of hemiplegic limbs to different extent,and were conformed by CT or MRI.There were 9 males and 6 females,aging 16-87 years old,the median age was 51.7 years,and all were right handed.Fifteen right-handed normal subjects,who were matched by age and sex with the patients in the cerebral infarction group,were selected from the relatives of patients and physicians of the Imaging Department as the control group.All the subjects were informed and agreed with the study.METHODS:The patients with acute cerebral infarction and subjects in the control group received MR diffusion tensor imaging(DTI)with GE 1.5 T nuclear magnetic resonance system,fiber tracking with the software of dTV-Ⅱ.Fractional anisotropy(FA)maps and three-dimensional tractography of bilateral CST of all patients were created.Displacement,continuity and destroy of fibrous bands were observed.At the same time,muscle strength of ipsilateral hand of patients with cerebral infarction was measured with Brunnstrom standard.The correlation between the severity of CST injury and the muscle strength of ipsilateral hand was analyzed with spearman correlation analysis.MAIN OUTCOME MEASURES:①FA values in the infarcted sites and those in the contralateral corresponding sites of patients with cerebral infarction;②CST manifestations in the patients with cerebral infarction and the control group.RESULTS:All the 30 testees were involved in the analysis of results.①The FA values in infarcted sites of white matter were significantly lower than those in the contralateral ones(t=4.570,P<0.001).②In the control group,bilateral CST were reconstructed,they originated from precentral gyrus,went downwards to internal capsule,and extended to pontine and medulla oblongata,each fiber had good uniformity in continuous form.In the patients with cerebral infarction,the forms of contralateral CST were consistent with those in the control group with good continuity.Due to the involvement by the infarcted site to different extents,the ipsilateral CST manifested as continuous interruption and loss of uniformity in anatomic structure and form.The CST involvements were divided into three grades:integrated CST for grade 1(n=2);integrated CST but compressed or displaced for grade 2(n=5);interrupted CST for grade 3(n=8).③The severity of CST injury was obviously correlated with the muscle strength of the ipsilateral hand(r=0.888,P<0.05).CONCLUSION:①CST is injured to different extents in patients with acute cerebral infarction,and the severity of injury is associated with muscle strength.It is indicated that it can be used to judge the prognosis of rehabilitative treatment.②DTT can directly display the status of pyramidal tract more three-dimensionally. 展开更多
关键词 CST evaluation of corticospinal tract injury with three-dimensional diffusion tensor tract in patients with acute cerebral infarction
暂未订购
Metropolitan digital library services evaluation: Measures and approaches
18
作者 LIU Wei LOU Xiangying ZHANG Chunjing 《Chinese Journal of Library and Information Science》 2008年第1期38-51,共14页
This paper reviews the evaluation model and measurements according to metropolitan digital library activities. Through literature review and historical research, the authors argue that the evaluation of the digital li... This paper reviews the evaluation model and measurements according to metropolitan digital library activities. Through literature review and historical research, the authors argue that the evaluation of the digital library(DL) is still in a research stage and not yet of value to the real achievement of the DL in operation. Because of the variety of the understandings of the digital library and the complexity of the technical factors, we can put forward a set of reference models, measurements and approaches to combine with the various researches on the evaluation theory and practice in the digital library area. The authors primarily discuss and conclude with a digital library evaluation model and measurement index system according to the requirements of the world metropolitan libraries. 展开更多
关键词 digital library digital resources evaluation evaluation model evaluation index system
原文传递
A study of CALIS evaluation indicator system for digital resources and its practical application considerations
19
作者 XIAO Long LI Haoling XU Cheng 《Chinese Journal of Library and Information Science》 2008年第Z1期30-47,共18页
Based on our theoretical studies and practical experience related to the digital resource evaluation activities,which were undertaken jointly by CALIS and Peking University Library,this paper discusses the targeted ob... Based on our theoretical studies and practical experience related to the digital resource evaluation activities,which were undertaken jointly by CALIS and Peking University Library,this paper discusses the targeted object,content,the structure and the attributes of CALIS evaluation indicator system for digital resources.We also offer a detailed guideline for professional practice in terms of using this particular indicator system to evaluate the viability and the collection strength of a given digital library. 展开更多
关键词 CALIS digital resources evaluation evaluation indicator evaluation content Application guideline
原文传递
上一页 1 2 152 下一页 到第
使用帮助 返回顶部