卷首语

中国首条铁路是1876年英国公使提议建造的吴淞铁路。虽然是英帝国主义采用非法手段修建的铁路,并且在通车16个月后就被拆除,但它开辟了中国铁路的先河。     

科技：中国铁路发展的火车头

铁路是技术革命的产物。从世界铁路发展史看,铁路在其诞生和发展的各个历史时期,都受到当时科技发展的推动,受到当时最新科技成果的滋润和催动。离开了科技进步,铁路的发展只会停滞不前,甚至出现倒退。第二次世界大战以后,由于铁路科技创新速度相对公路和航空的降低,铁路所占运输市场的份额不断下降,铁路的发展出现了滞涨和衰退。60年代后,随着牵引     

徐家汇空中连廊二期EPC工程中设计与施工融合探究

随着经济社会的发展,城市更新项目日益增多。徐家汇空中连廊项目构建了各商业体之间联动纽带,提升了商圈的商业能级,是城市更新的典型项目,具有现场条件复杂、实施难度大、景观要求高等特点。着重介绍了徐家汇空中连廊二期工程的设计方案及设计施工相融合的实施经验,采用BIM技术进行设计施工一体化管理,创新的采用结构、装饰一体化集成拼装施工技术,降低了安全风险,提高了安装质量,缩短了施工工期,为类似工程提供实践经验。     

Evaluating the maneuverability of a new type of self-propelled barge

A new type of self-propelled barge was designed specifically for use on the Chishui River. This paper presents experimental results of its performance from tests in water of different depths,while bearing different loads. For test purposes,one of the best self-propelled barges from the Chishui River was used as a performance reference. The comparison showed that the new design has better maneuvering performance.     

COVID-19 Interpretable Diagnosis Algorithm Based on a Small Number of Chest X-Ray Samples

The COVID-19 medical diagnosis method based on individual's chest X-ray (CXR) is achieved dif-ficultly in the initial research,owing to difficulties in identifying CXR data of COVID-19 individuals.At the beginning of the study,infected individuals' CXRs were scarce.The combination of artificial intelligence (AI)and medical diagnosis has been advanced and popular.To solve the difficulties,the interpretability analysis of AI model was used to explore the pathological characteristics of CXR samples infected with COVID-19 and assist in medical diagnosis.The dataset was expanded by data augmentation to avoid overfitting.Transfer learning was used to test different pre-trained models and the unique output layers were designed to complete the model training with few samples.In this study,the output results of four pre-trained models in three different output layers were compared,and the results after data augmentation were compared with the results of the original dataset.The control variable method was used to conduct independent tests of 24 groups.Finally,99.23％ accuracy and 98％recall rate were obtained,and the visual results of CXR interpretability analysis were displayed.The network of COVID-19 interpretable diagnosis algorithm has the characteristics of high generalization and lightweight.It can be quickly applied to other urgent tasks with insufficient experimental data.At the same time,interpretability analysis brings new possibilities for medical diagnosis.     

The process analysis and improvement of the slender and flat shaft of track recorder

1Introduction Thetrackrecorderisanimportanttechnicalinstru mentsproducedforamarineship.Itisusedforreal timedrawingofaship’scourse.Thecontrolsystemof thetrackrecorderisanopenloopsystemdrivenbya step by stepmotor,sotheprecisionofthetransforma tionpartdirec…     

曹妃甸通岛路工程动静荷载变形数值分析

应用二维有效应力法和EFESD计算程序分析了静力荷载、地震动力荷载和列车动荷载作用下稳定和变形情况。静力计算结果表明在路基稳定变形时,最大沉降约为80 cm,最大水平位移约为35 cm。动力计算表明,在地震荷载和列车荷载作用下路基均不会产生液化。地震荷载作用下,沉降约为35 cm,水平位移约为15 cm。列车荷载作用下,沉降约为120 cm,水平位移约为50 cm。     

京山桥钢桥面SMA铺装层设计与施工技术

介绍沥青玛蹄脂混合料(SMA)的强度机理和优良性能,阐述SMA-13混合料的设计、拌和生产、摊铺、碾压施工中的技术要点。