检索结果-南通市图书馆

International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 763-769页

作者： Dong-nan Huang Zhi-hao Zhang Jing-yuan Li Jian-xin Xie Advanced Materials and Technologies Institute University of Science and Technology Beijing Beijing 100083 China School of Materials Science and Engineering Inner Mongolia University of Technology Huhhot 010051 China

A reconstruction technology of finite element meshes based on reversal engineering was applied to solve mesh penetration and separation in the finite element simulation for the divergent extrusion. The 3D numerical simulation of the divergent extrusion process in- cluding the welding stage for complicated hollow sections was conducted. Based on the analysis of flowing behaviors, the flowing velocities of the alloy in portholes and near the welding planes were properly controlled through optimizing the expansion angle as well as porthole ar- eas and positions. After the die structure optimization, defects such as warp, wrist, and the wavelike are eliminated, which improves the sec- tion-forming quality. Meanwhile, the temperature distribution in the cross section is uniform. Especially, the temperature of the C-shape notch with a larger thickness is lower than that of other regions in the cross section, which is beneficial for balancing the alloy flowing velocity.

关键词： numerical simulation extrusion metal forming metal flow reconstruction

A Single Bundle Anterior Cruciate Ligament reconstruction (ACL-R) Using Hamstring Tendon Autograft and Tibialis Anterior Tendon Allograft:A Comparative Study

在线全文

学校读者我要写书评

暂无评论

Current Medical Science 2018年第5期38卷 818-826页

作者： Saroj Rai Sheng-yang JIN Bimal RAI Nira TAMANG Wei HUANG Xian-zhe LIU Chun-qing MENG Hong WANG Department of Orthopaedics Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Department of Radiology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China School of Nursing Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China National Trauma Center National Academy of Medical SciencesKathmandu 44600Nepal

The main purpose of this study patients undergoing a single bundle anterior was to compare the clinical outcomes of cruciate ligament reconstruction (ACL-R) of using quadrupled hamstring (4HT)autografts and two-strand tibialis anterior (2TA) aUografts,and to find out the rate of graft failure and possible causes.We hypothesized that there would be no difference in the clinical outcome,and graft failure would be associated with the use of small sized allograft in young active males with high demand of sports activities.We retrospectively evaluated 222 patients (male,n=167,female,n=55) undergoing ACL-R between January 2010 and July 2014.Of 222 patients,115 were included in the 4HT autograft group and 107 patients in the 2TA allograft group.Inclusion criteria were primary unilateral ACL-R with a minor MCL (

关键词： anterior cruciate ligament reconstruction autograft allograft hamstring tendon tibialis anterior tendon

Practical BRDF reconstruction using reliable geometric regions from multi-view stereo

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computational Visual Media 2019年第4期5卷 325-336页

作者： Taishi Ono Hiroyuki Kubo Kenichiro Tanaka Takuya Funatomi Yasuhiro Mukaigawa Nara Institute of Science and Technology IkomaNara 630-0192Japan

In this paper,we present a practical method for reconstructing the bidirectional reflectance distribution function(BRDF)from multiple images of a real object composed of a homogeneous material.The key idea is that the BRDF can be sampled after geometry estimation using multi-view stereo(MVS)techniques.Our contribution is selection of reliable samples of lighting,surface normal,and viewing directions for robustness against estimation errors of MVS.Our method is quantitatively evaluated using synthesized images and its effectiveness is shown via real-world experiments.

关键词： BRDF reconstruction multi-view stereo(MVS) photogrammetry rendering

Contemporary approach to soft-tissue reconstruction of the lower extremity after trauma

在线全文

学校读者我要写书评

暂无评论

Burns & Trauma 2021年第1期9卷 351-363页

作者： Matthew R.Zeiderman Lee L.Q.Pu Division of Plastic&Reconstructive Surgery Department of SurgeryUniversity of CaliforniaDavisSacramentoCAUSA

The complex lower extremity wound is frequently encountered by orthopedic and plastic surgeons.Innovations in wound care,soft tissue coverage and surgical fixation techniques allow for improved functional outcomes in this patient population with highly morbid injuries.In this review,the principles of reconstruction of complex lower extremity traumatic wounds are outlined.These principles include appropriate initial evaluation of the patient and mangled extremity,as well as appropriate patient selection for limb salvage.The authors emphasize proper planning for reconstruction,timing of reconstruction and the importance of an understanding of the most appropriate reconstructive option.The role of different reconstructive and wound care modalities is discussed,notably negative pressure wound therapy and dermal substitutes.The role of pedicled flaps and microvascular free-tissue transfer are discussed,as are innovations in understanding of perforator anatomy and perforator flap surgery that have broadened the reconstruction surgeon’s armamentarium.Finally,the importance of a multidisciplinary team is highlighted via the principle of the orthoplastic approach to management of complex lower extremity wounds.Upon completion of this review,the reader should have a thorough understanding of the principles of contemporary lower extremity reconstruction.

关键词： Lower extremity Soft tissue reconstruction Trauma Surgical approach

Extrapolation reconstruction of wind pressure fields on the claddings of high-rise buildings

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第3期13卷 653-666页

作者： Yehua SUN Guquan SONG Hui LV School of Civil Engineering and Architecture Nanchang UniversityNanchang 330033China Jiangxi Institute of Economic Administrators Nanchang 330038China

Recent research about reconstruction methods mainly used the interpolation reconstruction of the fluctuating wind pressure field on the surface.However,to investigate wind pressure at the edge of the building,the work presented in this paper focuses on the extrapolation reconstruction of wind pressure fields.Here,we propose an improved proper orthogonal decomposition(POD)and Kriging method with a von Karman correlation function to resolve this issue.The studies show that it works well for not only interpolation reconstruction but also extrapolation reconstruction.The proposed method does require determination of the Hurst exponent and other parameters analysed from the original data.Hence,the fluctuating wind fields have been characterized by the von Karman correlation function,as an a priori function.Compared with the cubic spline method and different variogram,preliminary results suggest less time consumption and high efficiency in extrapolation reconstruction at the edge.

关键词： extrapolation reconstruction proper orthogonal decomposition Kriging method von Karman function Hurst exponent rescaled range analysis

Fast gradational reconstruction for Fourier ptychographic microscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2017年第11期15卷 78-83页

作者：张继洲许廷发王杏陈思凝倪国强 School of Optoelectronics Image Engineering and Video Technology Lab Beijing Institute of Technology Beijing 100081 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of China Beijing 100081 China

We develop an improved global reconstruction method for Fourier ptychographic microscopy,a newly reported technique for wide-field and high-resolution microscopic observation.The gradational strategy and graphic processing unit computing are applied to accelerate the conventional global reconstruction method.Both simulations and experiments are carried out to evaluate the performance of our method,and the results show that this method offers a much faster convergence speed and maintains a good reconstruction quality.

关键词： faster gradation sequential iteration accelerate microscopic illumination captured reconstruction overlap

Displacement Response reconstruction of Slender Flexible Structures Based on Cubic Spline Fitting Method

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2019年第2期33卷 226-236页

作者： HAN Qing-hua MA Ye-xuan FENG Xin-xin XU Wan-hai State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University School of Civil Engineering Tianjin University

How to reconstruct a dynamic displacement of slender flexible structures is the key technology to develop smart structures and structural health monitoring(SHM), which are beneficial for controlling the structural vibration and protecting the structural safety. In this paper, the displacement reconstruction method based on cubic spline fitting is put forward to reconstruct the dynamic displacement of slender flexible structures without the knowledge of modeshapes and applied loading. The obtained strains and displacements are compared with the results calculated by ABAQUS to check the method's validity. It can be found that the proposed method can accurately identify the strains and displacement of slender flexible structures undergoing linear vibrations, nonlinear vibrations, and parametric vibrations. Under the concentrated force, the strains of slender flexible structures will change suddenly along the axial direction. With locally densified measurement points, the present reconstruction method still works well for the strain concentration problem.

关键词： displacement reconstruction cubic spline fitting slender flexible structures linear vibrations parametric vibrations nonlinear vibrations

Comparison between uncut Roux-en-Y and Roux-en-Y reconstruction after distal gastrectomy for gastric cancer: A meta-analysis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2018年第24期24卷 2628-2639页

作者： Ming-Ming Sun Yi-Yi Fan Sheng-Chun Dang Department of General Surgery The Affiliated Hospital of Jiangsu University

AIM To compare uncut Roux-en-Y(U-RY) gastrojejunostomy with Roux-en-Y(RY) gastrojejunostomy after distal gastrectomy(DG) for gastric cancer.METHODS A literature search was conducted in Pubmed, Embase, Web of Science, Cochrane Library, Science Direct, Chinese National Knowledge Infrastructure, Wanfang, and China Science and Technology Journal Database to identify studies comparing U-RY with RY after DG for gastric cancer until the end of December 2017. Pooled odds ratio or weighted mean difference with 95% confidence interval was calculated using either fixed-or random-effects models. Perioperative outcomes such as operative time, intraoperative blood loss, and hospital stay; postoperative complications such as anastomotic bleeding, stricture and ulcer, reflux gastritis/esophagitis, delayed gastric emptying, and Roux stasis syndrome; and postoperative nutritional status(serum hemoglobin, total protein, and albumin levels) were the main outcomes assessed. Metaanalyses were performed using RevM an 5.3 software.RESULTS Two randomized controlled trials and four nonrandomized observational clinical studies involving 403 and 488 patients, respectively, were included. The results of the meta-analysis showed that operative time [weighted mean difference(WMD):-12.95; 95%CI:-22.29 to-3.61; P = 0.007] and incidence of reflux gastritis/esophagitis(OR: 0.40; 95%CI: 0.20-0.80; P = 0.009), delayed gastric emptying(OR: 0.29; 95%CI: 0.14-0.61; P = 0.001), and Roux stasis syndrome(OR: 0.14; 95%CI: 0.04-0.50; P = 0.002) were reduced; and the level of serum albumin(WMD: 0.71; 95%CI: 0.24-1.19; P = 0.003) was increased in patients undergoing U-RY reconstruction compared with those undergoing RY reconstruction. No differences were found with respect to intraoperative blood loss, hospital stay, anastomotic bleeding, anastomotic stricture, anastomotic ulcer, the levels of serum hemoglobin, and serum total protein. CONCLUSION U-RY reconstruction has some clinical advantages over RY reconstruction after DG.

关键词： Roux-en-Y Gastric cancer Meta-analysis Distal gastrectomy reconstruction Uncut

Automatic three-dimensional reconstruction based on four-view stereo vision using checkerboard pattern

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2017年第5期24卷 1063-1072页

作者：熊杰仲思东刘勇屠礼芬 School of Electronic Information Wuhan University School of Physics and Electronic Information Engineering Hubei Engineering University

An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable or similar features of binocular images. In order to reduce the probability of mismatching and improve the measure precision, a four-camera measurement system which can add extra matching constraints and offer multiple measurements is applied in this work. Moreover, a series of different checkerboard patterns are projected onto the object to obtain dense feature points and remove mismatched points. Finally, the 3D model is generated by performing Delaunay triangulation and texture mapping on the point cloud obtained by four-view matching. This method was tested on the 3D reconstruction of a terracotta soldier sculpture and the Buddhas in the Mogao Grottoes. Their point clouds without mismatched points were obtained and less processing time was consumed in most cases relative to binocular matching. These good reconstructed models show the effectiveness of the method.

关键词： three-dimensional reconstruction four-view stereo vision checkerboard pattern dense point

Two Accelerating Techniques for 3D reconstruction

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2002年第3期17卷 362-368页

作者：刘世霞胡事民孙家广 Department of Computer Science and Technology Tsinghua University Beijing 100084 P.R. China

Automatic reconstruction of 3D objects from 2D orthographic views has been a major research issue in CAD/CAM. In this paper, two accelerating techniques to improve the efficiency of reconstruction are presented. First, some pseudo elements are removed by depth and topology information as soon as the wire-frame is constructed, which reduces the searching space. Second, the proposed algorithm does not establish all possible surfaces in the process of generating 3D faces. The surfaces and edge loops are generated by using the relationship between the boundaries of 3D faces and their projections. This avoids the growth in combinational complexity of previous methods that have to check all possible pairs of 3D candidate edges.

关键词： engineering drawing wire-frame reconstruction