课程文献中心 更多>>

关键词： cervical artery dissection   high-intensity transient signals   ischemic stroke   transcranial Doppler  

摘要： Background Cervical artery dissection (CAD) is a common cause of ischemic stroke in young adults. Local blood clot formation and distal emboli are the key mechanisms for the development of stroke in patients with CAD. Microemboli distal to the dissection point can be detected as high-intensity transient signals (HITS) using transcranial Doppler (TCD). Despite this unique capability, TCD is used inconsistently in the management of CAD. In this international survey, we aim to explore the frequency and potential barriers to TCD use in CAD. Method This study was an international electronic survey, based on the Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection (STOP-CAD) study, aiming at evaluating the use of TCD in diagnosing and managing CAD patients. A comprehensive questionnaire was developed to gather insights into the current practices, perceptions, and potential barriers to the effective use of TCD in participating centers. The collected data was then analyzed. Results Fifty-eight medical centers with advanced stroke care capabilities from Europe and United States participated in this study. Half (29 out of 58) of the sites routinely perform TCD on CAD patients, particularly in the presence of carotid or vertebral artery stenosis, complete carotid occlusion, and early neurologic deterioration. The primary reason for participating institutions not performing TCD was because its results would not change their practice. The protocol for TCD monitoring and managing HITS-positive CAD patients varied among centers but transitioning from antiplatelet to anticoagulant was the most common practice in this patient population. Conclusion Half of the stroke centers in our survey routinely perform TCD monitoring for CAD patients. The detection of HITS in CAD patients is a warning sign for providers, which may prompt a change in secondary stroke prevention management. However, a standard protocol for performing TCD in CAD and treatment recommendations

关键词： SRAM   CAM   PFCAM   SCPF CAM   HSCPF CAM  

摘要： The switching speed and driving capability have been enhanced by scaling the transistor size to nanoscale. The limitations in using MOSFET are that the short channel effects such as leakage current, subthreshold voltage, etc. thereby the Complementary Metal Oxide Semiconductor (CMOS) scaling is challenging *** leads to the emergence of multi-gate devices, such as Fin Field Effect Transistor (FinFET) and Double Gate FinFET (DG-FinFET), which reduces the short channel effect. Now, a days memory plays a vital role in Integrated Circuits (IC), so the size of it must be scaled down to reduce the overall leakage andinstead of CMOS an advanced MOSFET such as FinFET can be used to avoid SCE. The area of the memory Static Random Access Memory (SRAM) is reduced by eliminating the two-load transistor. The novel 4T SRAM is designed at 10 nm 0.75 v FinFET Technology and compared with 14 nm Technology that is inbuilt into content addressable memory (CAM) to reduce the power consumption of CAM. The results show that the proposed design improves on a voltage basis and the complexity of the circuit is reduced by about 23% in terms of transistor count compared with the other conventional techniques. The 10 nm FinFET Hybrid Self Controlled - PreCharge Free (HSCPF) CAM design is best-suitable for low-power applications.

关键词： 铁路工程制图   CAD   新形态教材   教学改革   实践应用  

摘要： 本文旨在论述《铁路工程制图与CAD》新形态教材开发思路、目标、现状分析、研究内容和实践应用。文章强调了以学生为核心的教育观念,并根据行业的实际需求来设定教学目标。分析了现行教材内容存在局限性、教学方法和教材不相适应、实践环节欠缺等问题。基于此,提出了新形态教材内容创新之处,主要表现为融合最新铁路工程案例、加入CAD技术前沿运用、优化教材内容设计与呈现形式等。并探讨了新形态教材在教学中的实施情况和学生学习效果的评估。通过上述研究,其目的在于提高铁路工程制图及CAD教学质量及成效,培养出适应产业需要的高素质技术技能型人才。

摘要： The aim of this study was to investigate the color changes of three different CAD/CAM ceramic materials with glazing and mechanical polishing surface treatments after soaking in coffee solution.

关键词： 三视图   立体图形   CAD技术   三维建模技术   学生探究   发散思维   空间想象能力   课程标准  

摘要： 《普通高中通用技术课程标准(2017年版2020年修订)》要求学生“运用简易绘图软件绘制简单的三视图,用恰当的技术语言与他人交流设计思想和成果”。三视图是普通高中通用技术学科中的一个重要专题。教师开展三视图教学意在培养和提高学生的发散思维及空间想象能力。为弥补该专题内容抽象、难以理解,且教学方式枯燥乏味的不足,教师可以利用三维建模技术为学生充分展示立体图形的三视图。为此,笔者尝试借助计算机辅助设计(CAD)技术开展三视图教学,让学生探究三维造型,更加直观和深入地理解三视图相关知识,从而提高空间想象能力和学习效率。

关键词： 可解释深度学习   梯度类加权激活映射   调制识别   时频分析  

摘要： 针对时频深度学习调制识别方法存在可解释性差的问题,提出一种基于时频梯度加权类激活映射(GradCAM)的调制识别网络可解释框架.该框架通过时频Grad-CAM可视化深度模型中隐含层的关键特征,从视觉上解释网络隐含层提取的时频深度特征对于正确与错误识别中的作用,揭示低信噪比环境下网络性能下降的内在机理,并通过量化和排序网络中每层不同卷积核的贡献值来判断网络的冗余程度.仿真实验结果验证了基于时频Grad-CAM的调制识别网络可解释性框架的有效性;可解释分析结果表明,在低信噪比环境下,网络特征提取区域有大量噪声存在,且本文所测试的调制识别网络冗余程度较为严重.

关键词： DL   deep learning   OCT   optical coherence tomography   CNN-LSTM   convolutional neural networks + long short-term memory   PU   positive unlabeled   OLS   ordinary least square   RNFL   retinal nerve fiber layer   AI   artificial intelligence   SAP   standard automated perimetry   ONH   optical nerve head   SD-OCT   spectral domain OCT   PSD   pattern standard deviation   ICD   international classification of diseases   CPT   current procedural terminology   CNN   convolutional neural networks   LSTM   long short-term memory   ANN   artificial neural networks   RNN   recurrent neural networks   ROC   receiver operator characteristic   AUC   area under the curve   ML   machine learning   CAM   class activation maps  

摘要： PurposeTo develop deep learning (DL) algorithm to detect glaucoma progression using optical coherence tomography (OCT) images, in the absence of a reference standard. DesignRetrospective cohort study. MethodsGlaucomatous and healthy eyes with ≥5 reliable peripapillary OCT (Spectralis, Heidelberg Engineering) circle scans were included. A weakly supervised time-series learning model, called noise positive-unlabeled (Noise-PU) DL was developed to classify whether sequences of OCT B-scans showed glaucoma progression. The model used 2 learning schemes, one to identify age-related changes by differentiating test sequences from glaucoma vs healthy eyes, and the other to identify test-retest variability based on scrambled OCTs of glaucoma eyes. Both models' bases were convolutional neural networks (CNN) and long short-term memory (LSTM) networks which were combined to form a CNN-LSTM model. Model features were combined and jointly trained to identify glaucoma progression, accounting for age-related loss. The DL model's outcomes were compared with ordinary least squares (OLS) regression of retinal nerve fiber layer (RNFL) thickness over time, matched for specificity. The hit ratio was used as a proxy for sensitivity. ResultsEight thousand seven hundred eighty-five follow-up sequences of 5 consecutive OCT tests from 3253 eyes (1859 subjects) were included in the study. The mean follow-up time was 3.5 ± 1.6 years. In the test sample, the hit ratios of the DL and OLS methods were 0.498 (95%CI: 0.470-0.526) and 0.284 (95%CI: 0.258-0.309) respectively ( P < .001) when the specificities were equalized to 95%. ConclusionA DL model was able to identify longitudinal glaucomatous structural changes in OCT B-scans using a surrogate reference standard for progression.

关键词： 凸轮–挺柱   润湿性梯度   限量供油   自集油增强  

摘要： 设计制备了一种圆弧形疏油区与原始亲油区交替排列的图案化功能表面,实现少量润滑油的自动聚集,探索其对凸轮–挺柱副限量润滑性能的改善。结果表明,涂层功能表面使接触副表面产生润湿性梯度,限量润滑油在无外部力驱动情况下定向流动,改善了接触区供油进而实现改善润滑性能的目的。亲油轨道宽度对润滑油回流影响并非一致的,合适的宽度设计能够产生良好的集油效果;高黏度润滑油受到钉扎作用阻碍其挤压阶段的向外流动;供油量降低至0.5μL时运动副已处于严重乏油状态,集油表面无法发挥改善润滑的作用。

关键词： 非破坏性方法   纺织品   甲醛   检测  

摘要： 选用市场上常见的722 s型可见分光光度计、UV-1801型紫外分光光度计和ONIBA型紫外/可见分光光度计对纺织品进行甲醛检测,评估3种仪器的性能指标,比较检出限、测定下限和测定上限。提出纺织品甲醛检测的非破坏性方法,并与现有GB/T 2912.1—2009《纺织品甲醛的测试第1部分:游离和水解的甲醛(水萃取法)》(破坏性方法)进行对比。在不同时间及温度下对非破坏性纺织品甲醛质量浓度的测定,确定了较佳的试验条件及经济型的分光光度计,可为纺织品甲醛检测中分光光度计的选择提供参考。

关键词： 数字化期刊   产业用纺织品   高校科技期刊   期刊中心   中国学术期刊   核心学术期刊   案例库   邮发代号  

摘要： 《产业用纺织品》(月刊,ISSN 1004-7093,CN 31-1595/TS),大16开,全彩色印刷,定价12.00元/册,全年144.00元,邮发代号:4-492。《产业用纺织品》创刊于1983年,由教育部主管,东华大学、全国产业用纺织品科技情报站主办,中国产业用纺织品行业协会协办,东华大学期刊中心编辑出版,是全国产业用纺织品领域具有权威性的期刊之一。作为《中国学术期刊影响因子年报》统计源期刊,《产业用纺织品》已入编中国学术期刊(网络版)、万方数据-数字化期刊群、中文科技期刊数据库、超星期刊域出版平台等,并多次入编《中文核心期刊要目总览》,入选RCCSE中国准核心学术期刊、CACJ中国应用型扩展期刊,为第五届上海市高校科技期刊案例库特色科技期刊。