二齿差针摆行星传动中摆线轮等效代换齿廓的试验研究

通过样机试验的手段来检验,用一条整枝短幅外摆线的等距贡线来代换二齿差摆线轮齿廓的正确性和可行性。采用比较的方法,即在试验台上对装有两种不同齿廓摆线轮的样机,分别进行温升,噪音,振动和效率等参数的对比试验。试验结果表明,等效代换齿廓与原齿廓的传动性能比较,基本相同或略优。从而进一步验证了该理论的正确性,并为该技术的应用提供了依据。     

太平天国的水军太平军水营

以洪秀全为首的农民军自金田起义后,更名为太平军。他们不断与清军作战,转战长江南北,并设立“水路军”,分别在陆上和水中与清军展丌了作战。虽然轰轰烈烈的太平天国运动最终以失败告终,但是“水军”从兴起到结束的十余年时间却在太平天困的战斗史上占据了非常重要的地位。     

特种半潜式无人航行器的优化设计

提出一种新型特种半潜式无人航行器方案,并对该航行器方案开展主尺度初步拟定和舱室划分等总体设计工作。基于STAR CCM+软件对该型航行器的水动力性能进行数值仿真分析,分析结果可作为推进系统设计及船型主尺度优化的依据。结合实际工程产品需求分析制约航行器推进系统设计的影响因素,分析续航力、航速、主机功率及电池质量之间的匹配关系,同时提出基于约束关系的主尺度优化方法。最后针对性能校核及数值仿真中发现的问题,提出半潜式无人航行器的进一步优化方案。     

Flexible Overlap Technology for the Lining Trolley of Single-track Railway Tunnels北大核心CSCD

Falling-off of rock piece at tunnel arch and invert heave are the main potential safety problems affecting normal operation of the railway tunnel. The reasons causing falling-off of rock piece include squeezing by lining trol⁃ ley at construction joint, concrete cutting by cantilever end of water stop at construction joint, construction cold joint at arch, concrete quality deficiency and so on. To eliminate the falling-off of rock piece at tunnel arch caused by rig⁃ id overlap, modification of lining trolley and the flexible overlap technique combining tray with rubber gasket were adopted during the construction of Nuwashan tunnel on China-Laos railway, and the potential quality problem due to rigid overlap at construction joint of tunnel lining were effectively solved. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Experimental and Numerical Study on the Behaviors of Deep-Buried Water-Storage and Drainage Shield Tunnels北大核心CSCD

Deep-buried water-storage and drainage shield tunnels, which are different from road and subway shield tunnels in terms of computation theory, construction technology and operation maintenance, would bear high inner water pressure and large earth pressure. In view of the change of the bearing mode for the lining structure of water-storage and drainage shield tunnels, a full-ring test and numerical analysis are carried out to study the influence of inner water pressure, staggered joint assembly and bolt installation types on the behaviors of water-storage and drainage shield tunnels. The results show that the deformation of the straight-jointed water-storage and drainage shield tunnel varies greatly from the state of empty water to that of full water; and the vertical and horizontal convergence deformations of the tunnel with inner water pressure of 0.6 MPa are 2.2 times and 3.2 times of that without inner water pressure, respectively. The convergence deformation, and the maximum joint opening and bolt tension of stagger-jointed lining structure decrease by 15%-25% and 25%- 40%, respectively, compared with that of the straight-jointed water-storage and drainage shield tunnel. The bolts at the segmental joints will yield because of the increase of inner water pressure and the first occurrence of bolt yield phenomenon is located near the position on the lining structure which is under the action of maximum negative bending moment; because the failure of shield tunnel is always caused by the yield of joint bolts, this position is the weak point for the deep-buried water-storage and drainage shield tunnel. For the water-storage and drainage shield tunnel based on the connection with double rows of bolts, the bolts near the outer arc surface of segmental joints in the area of 90 degree in the vault and arch bottom can be removed; the bolts near the inner arc surface of the segmental joints within the 90 degree of the haunch must be installed, otherwise, the tensile force of the bolts at the segmental joint near the maximum negative bending moment will increase by 5%-14%. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

新型船舶燃油预热转运技术应用分析

针对传统船舶燃油加热技术存在的一些问题,介绍了一种新型燃油预热转运技术应用原理,并对该技术进行了实用性分析,提出了新船加装和老船改造该技术系统应考虑的相关问题。最终得出结论:新型燃油预热技术操作简捷,系统容易管理,实用性强,大大降低了蒸汽使用量,达到了节能减排双重功效,是值得应用于船舶的加热技术,对航运企业有一定借鉴意义和参考价值。     

What encourages people to carpool? An evaluation of factors with meta-analysis

Non-household carpools (where two or more commuters from different residences travel together in the same private vehicle) bring public benefits. To encourage and incentivise it, transport practitioners and researchers must understand its private motivations and deterrents. Existing studies often report conflicting results or non-generalisable findings. Thus, a quantitative systematic review of the literature body is needed. Using meta-analysis, this study synthesised 22 existing empirical studies (representing over 79,000 observations) to produce an integrated review of the carpooling literature. The meta-analysis determined 24 non-household carpooling factors, and their effect sizes. Factors such as number of employees (\(\bar{r} = 0.42\)), partner matching programs (\(\bar{r} = 0.42\)), female (\(\bar{r} = 0.22\)) and fixed work schedule (\(\bar{r} = 0.15\)) were found to have strong effects on carpooling while judgmental factors (such as the motivation to save costs) only exhibited small influence (\(\bar{r} < 0.1\)). Based on the significant effects, the paper discussed prospects for improving carpooling uptake by developing: (i) target demographics, (ii) selling points for marketing, (iii) carpooling partner programs and (iv) multiple employer ‘super-pools’. The results warrant caution due to the small amount of studies synthesised. Transport practitioners might plan carpooling policies based on the findings; and transportation researchers might use the list of factors to model carpooling behaviour.     

58m多用途拖船下水计算分析

着重介绍了58m多用途拖船#2船在较低水位下水时采取的改善措施,对下水计算结果进行验证分析以确定下水计算的正确性。     

长沙-株州-湘潭区域轨道交通建设必要性分析

借助于长沙-株州-湘潭区域轨道交通建设必要性的研究,总结提出了适合区域轨道交通建设必要性分析体系.该体系分为三个层次:宏观层、中观层是及微观层.宏观层是从分析区域轨道交通功能定位及国内外城市群轨道交通发展趋势的角度来判断区域轨道交通建设的必要性;中观层是研究必要性分析框架的内容,将必要性分析分为交通需求的需要、规划上的需要、城市经济的需要、环境能源的需要等四大方面;微观层系针对中观层的框架内容进行与目标区域轨道交通建设必要性相符的深层分析.介绍了长沙-株州-湘潭区域轨道交通建设必要性分析的基本过程及内容.     

哈大铁路客专德惠制梁场箱梁混凝土蒸养和压浆施工工艺

结合哈大铁路客专德惠制梁场箱梁预制的施工经验,介绍了箱梁混凝土蒸养和压浆施工工艺,以及现行技术条件与传统箱梁压浆工艺的矛盾、压浆工艺的改良等。施工结果表明,取得了较好的实际效果,对类似箱梁施工有一定的借鉴意义。