课程文献中心 更多>>

关键词： Gasoline  

摘要： Significant uncertainty exists with regards to the migration history of hydrocarbons in the Catcher Area Development (CAD) region, West Central Shelf, UK Central North Sea. In this study, petroleum system modelling is carried out to understand the pathways, timing and processes involved in hydrocarbons migration from the Jurassic Kimmeridge Clay to the injectite dominated sandstone reservoirs of the CAD region. The Cromarty sandstones are identified as the lateral carrier of hydrocarbons from the graben area to the CAD reservoirs. Out of the six CAD fields, five were charged along a fill spill chain. During the charging process, the CAD system was mostly seal limited, with significant hydrocarbon leakage into the overburden. Hydrocarbon migration and gas leakage in the region continues today. The present-day accumulations of the CAD region are spill limited suggesting the potential for more discoveries westward. This study provides an understanding of why gas chimneys are widespread in the CAD region and how the quality of hydrocarbons in the different fields relates to one another and those of the wider region. It also supports the presence of prospects further SW of the CAD region. © 2024

关键词： CAD-CAM materials   Kubelka-Munk theory   Optical properties   Translucency parameter  

摘要： To evaluate and compare the optical properties and relative translucency parameter of CAD-CAM restorative materials.

关键词： 浙江绍兴   机器运转   纺织原料   园区发展   中东地区   产业园区   企业车间   纺织品  

摘要： 入冬时节,踏入紫云自治县产业园区,各企业车间内生产如火如荼,园区发展动力强劲、活力四溢。贵州德联纺织品有限公司车间内,机器运转、纱梭飞旋,工人们开足马力赶订单。“从2023年6月投入生产以来,公司接到的订单不断,今年公司已完成2000万元的产值。”公司负责人舒海兵说。贵州德联纺织品有限公司2022年从浙江绍兴转移至紫云,主要从事纺织原料、坯布以及纺织辅料加工。依托稳定的客源,公司国际市场主要出口美国和中东地区,国内主要销往浙江、广东等地。除了订单多,随着生产规模的不断扩大,公司也为当地群众就地就近就业提供了平台。

关键词： 病理性近视   脉络膜新生血管   微循环   血流密度   光学相干断层扫描血管成像  

摘要： 目的:应用光学相干断层扫描血管成像(OCTA)定量分析病理性近视(PM)继发脉络膜新生血管(mCNV)患者黄斑区组织结构及微循环的变化。方法:病例对照研究。随机纳入2020年5月至2021年2月于扬州大学附属苏北人民医院眼科确诊为PM的患者57例(60眼),其中PM合并脉络膜新生血管(CNV)患者30例(30眼)作为mCNV组,无合并CNV的PM患者27例(30眼)作为无CNV组,同时选择本院眼科门诊检查后正常且年龄与PM患者匹配的健康人29例(30眼)作为对照组。所有纳入对象均测量等效球镜度(SE)、眼轴长度(AL)、最佳矫正视力(BCVA)。采用OCTA测量黄斑中心凹无血管区(FAZ)面积、周长和血流密度(FVD);黄斑中心凹、旁中心凹及旁中心凹4个分区的全层(FRT)、内层(IRT)和外层视网膜厚度(ORT)及浅层(SVD)和深层视网膜血流密度(DVD);中心凹下脉络膜厚度(SFCT)和脉络膜毛细血管层血流密度(CC-VD)。采用方差分析比较3组间AL、SE、黄斑血流密度、视网膜厚度、FAZ相关指标、脉络膜厚度及血流密度等差异。结果:3组间黄斑中心凹的FRT、IRT、ORT及全层SVD、DVD、FVD、FAZ面积及周长、CC-VD总体差异均有统计学意义(F=3.41~11.14,P<0.05)。进一步组间比较显示,与对照组相比,mCNV组的中心凹FRT、IRT、ORT均明显增加(均P<0.05),全层及旁中心凹的SVD和DVD、颞侧及鼻侧的SVD、鼻侧及下方的DVD、FVD、CC-VD均明显降低(均P<0.05);无CNV组中心凹IRT、中心凹DVD均明显增加(P<0.05),全层和旁中心凹及4个分区的SVD、FVD、FAZ面积及周长均明显降低(均P<0.05);无CNV组和mCNV组的SFCT均明显降低,差异均有统计学意义(均P<0.001)。与无CNV组相比,mCNV组的中心凹FRT、ORT均明显增加(均P<0.001),中心凹DVD、旁中心凹及鼻侧DVD、CC-VD均明显降低(均P<0.05)。结论:mCNV患者黄斑区视网膜增厚、中心凹下脉络膜变薄,其中黄斑中心凹ORT变化最为明显,浅层及深层视网膜、黄斑中心凹、脉络膜毛细血管层的血流密度较正常人群降低。

关键词： 机械CAD   产教融合   三贴近四融入五结合  

摘要： 针对中职学校机械CAD课程教学效果欠佳的现状,立足于学生感性直观与动手实践的学习特性,创新性地提出了“三贴近、四融入、五结合”的教学新模式。“三四五”教学模式以产教融合、知行合一为核心理念,紧密契合时代需求,校企联手制定专业建设规划、人才培养方案及课程教材,持续推动机械CAD课程的改革创新。通过紧扣产业需求、企业实际和职业岗位,确保教学方向正确;融入行业标准、企业文化、工作规范和企业实例,形成“四融入”教学模块,实现行业、企业与学校的深度融合;并坚守“五结合”原则,即理论与实践、校内与校外、线上与线下、教与学互动以及考核与评价的综合运用,全面提升教学质量。经过五年的实践验证,“三四五”教学模式有效促进了机械CAD课程的产教融合,教学效果显著提升,学生在学业水平测试、技能竞赛及专项职业能力测试中均取得显著进步,有力推动了机电专业群的全面发展。这一教学模式不仅激发了学生的学习热情,也为中职课程改革与创新提供了宝贵的经验与参考,具有重要的理论价值和实践指导意义。

关键词： Energy loss comparison   cam mechanism   slider-crank mechanism   experimental mechanics  

摘要： The reduction of energy consumption in industrial processes is a challenge to be confronted within the framework of the United Nations' Sustainable Development Goals. The present study compares the energy loss per cycle of two kinematically equivalent mechanisms: a slider-crank and an eccentric cam with a translational roller follower. We use the work-energy theorem to evaluate energy losses by using a viscous friction model in a stationary regime. The innovation of this study lies in the energetic comparison to identify the best and worst alternatives by analyzing the contribution of their main geometrical parameters, such as crank length, rod-crank length ratio, roller radius and follower offset. The aim is to provide guidelines to help machinery designers to take relevant preliminary decisions that affect energy efficiency. Herein, we include analytical models, numerical simulations and experimental results using a test stand that can be adapted to other planar one degree-of-freedom mechanisms. In this context, we conclude that an eccentric cam mechanism with a big roller radius and no offset provides the best energetic efficiency among the aforementioned mechanisms.

关键词： Facial bone fracture   3D CT images   Artificial neural network   3D detection   Class activation map   Computer aided diagnosis  

摘要： AbstractBackground and objective:The incidence of facial fractures is on the rise globally, yet limited studies are addressing the diverse forms of facial fractures present in 3D images. In particular, due to the nature of the facial fracture, the direction in which the bone fractures vary, and there is no clear outline, it is difficult to determine the exact location of the fracture in 2D images. Thus, 3D image analysis is required to find the exact fracture area, but it needs heavy computational complexity and expensive pixel-wise labeling for supervised learning. In this study, we tackle the problem of reducing the computational burden and increasing the accuracy of fracture localization by using a weakly-supervised object localization without pixel-wise labeling in a 3D image space. Methods:We propose a Very Fast, High-Resolution Aggregation 3D Detection CAM (VFHA-CAM) model, which can detect various facial fractures. To better detect tiny fractures, our model uses high-resolution feature maps and employs Ablation CAM to find an exact fracture location without pixel-wise labeling, where we use a rough fracture image detected with 3D box-wise labeling. To this end, we extract important features and use only essential features to reduce the computational complexity in 3D image space. Results:Experimental findings demonstrate that VFHA-CAM surpasses state-of-the-art 2D detection methods by up to 20% in sensitivity/person and specificity/person, achieving sensitivity/person and specificity/person scores of 87% and 85%, respectively. In addition, Our VFHA-CAM reduces location analysis time to 76 s without performance degradation compared to a simple Ablation CAM method that takes more than 20 min. Conclusion:This study introduces a novel weakly-supervised object localization approach for bone fracture detection in 3D facial images. The proposed method employs a 3D detection model, which helps detect various forms of facial bone fractures accurately. The CAM algorithm

关键词： Bone tissue engineering   Endocultivation   Facial bone regeneration   Scaffolds  

摘要： Correction of bony mandibular defects is a challenge in oral and maxillofacial surgery due to aesthetic and functional requirements. This study investigated the potential of a novel hybrid scaffold for bone regeneration and degradation assessment of the ceramic within the omentum majus over 6 months and the extent to which rhBMP-2 as a growth factor, alone or combined with a hydrogel, affects regeneration.

关键词： Computer Aided Design (CAD)   Constructive Solid Geometry (CSG)   Dual-layer hybrid geometry   Monte Carlo particle transport  

摘要： The CAD and CSG hybrid modeling for the Monte Carlo particle transport simulation improves the geometric accuracy and calculation efficiency. We propose a CAD/CSG dual-layer hybrid geometric Monte Carlo particle transport method, which divides the geometry into two layers, the CAD layer and the CSG layer, and overlaps them to build up the hybrid geometric model for particle transport simulation. The new method's accuracy is verified to prove that the new method has the same accuracy as that of CSG modeling alone or CAD modeling alone. The efficiency advantages of the new method are tested to know that increasing the number of CSG surfaces and reducing the number of CAD surfaces improve the efficiency. The efficiency advantages begin to appear compared to CAD modeling alone when the ratio of the number of CSG surfaces to the number of CAD surfaces reaches 4:6, about an improvement of 10%. Increasing the proportion of CSG surfaces improves the efficiency advantages, and smaller geometric tolerances accentuate the efficiency advantage. © 2024 Elsevier Ltd

关键词： 纺织品   检测标准   质量监控   实证研究   监控体系构建  

摘要： 通过对纺织品检测标准及检测质量管理要求的概述,揭示了各标准间的异同及其背后的质量管理理念。进一步地,为缩小理论与实践之间的差距,构建了基于现有标准的质量监控体系。实证研究部分采用案例分析法,探讨了监控方法的实际应用,并通过成效评估,验证了方法的有效性。