起升动载激励下岸桥起升传动系统动态特性

为研究岸桥起升传动系统在起升复杂工况下的动态特性,建立了起升机构的动力学模型,模拟了传动系统所受的起升动载.考虑传动系统中齿轮副的时变啮合刚度和支撑刚度,建立了起升传动系统平移-扭转耦合的动力学模型,得到了电机从启动到匀速最后减速到停止的起升过程中传动系统各构件的振动响应,并对不同阶段的啮合力进行了频域分析.研究表明,传动系统各构件的扭转振动与起升动载有相同的变化趋势,且由于起升速度的变化,加速和减速阶段的啮合力频谱出现了边频带现象.     

对拉萨铁路货物运输发展的创新研究

文章分析了拉萨市现有的铁路资源现状,针对铁路货物运输发展所面临的主要问题提出了解决的措施。并结合高原货物运输的特点,提出了铁路货物运输在拉萨发展的建议。     

随机条件下基于存贮论的海运空箱调运仿真研究

基于存贮理论的思想,提出在港口设置阈值(D,U),即当港口空箱数量小于D时,调运空箱到港口直至达到D值;当港口空箱数量大于U时,把港口多余空箱装船运走。并以一条航线空箱总成本为目标函数,分别建立设置与未设置(D,U)值的成本计算模型,比较两种策略下模型的差异,并通过仿真的方法,计算出航程的总成本并进行比较,得出设置(D,U)值的优势并对设置值进行灵敏度分析。运算结果表明,设置(D,U)值的策略能够明显降低航线成本。     

A Decision Support Method for Truck Scheduling and Storage Allocation Problem at Container

Truck scheduling and storage allocation, as two separate subproblems in port operations, have been deeply studied in past decades. However, from the operational point of view, they are highly interdependent. Storage allocation for import containers has to balance the travel time and queuing time of each container in yard. This paper proposed an integer programming model handling these two problems as a whole. The objective of this model is to reduce congestion and waiting time of container trucks in the terminal so as to decrease the makespan of discharging containers. Due to the inherent complexity of the prob-lem, a genetic algorithm and a greedy heuristic algorithm are designed to attain near optimal solutions. It shows that the heuristic algorithm can achieve the optimal solution for small-scale problems. The solutions of small-and large-scale problems obtained from the heuristic algorithm are better than those from the genetic algorithm.     

Synthesis and Characterisation of Sulfated Zirconia Sol-Gel Systems

A set of sulfated zirconia xerogels were prepared using a one and two step hydrolysis method, in different vessels (open or closed) and varying the molar ratio R = [HNO₃]/[Zr(On-Pr)₄]. In order to verify the influence of these variables on the gel time and the final samples, physisorpion, quantitative analysis of the sulfate, DTA and DTG, X-ray diffraction at small (SAXS) and wide (WAXS) angles, and FTIR measurements, were employed. The main differences were found regarding samples with different values of R. For samples with R constant, the preparation method and the kind of container employed only slightly influenced the samples.     

Determination of Trace Leaching Phthalate Esters in Water and Urine from Plastic Containers by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

A sensitive method has been developed for determination of trace leaching phthalate esters (PAEs) in water and urine from plastic containers by direct immersion solid-phase microextraction (DI-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). The limits of detection (LODs) for PAEs in water and urine had values between 0.2–8 ng L^?1 and 4–70 ng L^?1, respectively. The proposed method was successfully used for quantification of trace PAEs in water in microwavable polypropylene containers heated by microwave irradiation and in the urine of patients treated with a glucose injection using polyvinyl chloride tubing.     

Evolution of lone pair of excess electrons inside molecular cages with the deformation of the cage in e2@C60F60 systems

For unusual e(2)@C(60)F(60)(I(h), D(6h), and D(5d)) cage structures with two excess electrons, it is reported that not only the lone pair in singlet state but also two single excess electrons in triplet state can be encapsulated inside the C(60)F(60) cages to form single molecular solvated dielectrons. The interesting relationship between the shape of the cage and the spin state of the system has revealed that ground states are singlet state for spherical shaped e(2)@C(60)F(60)(I(h)) and triplet states for short capsular shaped e(2)@C(60)F(60)(D(6h)) and long capsular shaped e(2)@C(60)F(60)(D(5d)), which shows a spin evolution from the singlet to triplet state with the deformation of the cage from spherical to capsular shape. For these excess electron systems, the three ground state structures have large vertical electron detachment energies (VDEs (I) of 1.720-2.283 eV and VDEs (II) of 3.959-5.288 eV), which shows their stabilities and suggests that the large C(60)F(60) cage is the efficient container of excess electrons.     

Assembly of Water‐Soluble,Dynamic, Covalent Container Molecules and Their Application in the Room‐Temperature Stabilization of Protoadamantene

The thermodynamically controlled reactions of water‐soluble tetraformylcavitand 2 with two equivalents of H₂N(CH₂)_nNH₂ (n=2–4) in the presence of a suitable templating guest give hemicarceplexes 1 a – c? guest, the yield of which depends on the match between size and shape of the guest and that of the inner phase. These hemicarceplexes are dynamic and dissociate upon addition of acid and reform upon basification. In water, they exchange guests through temporary hydrolysis of imine bonds. To test 1 b as molecular reaction flask, 3‐noradamantyldiazirine 6 was encapsulated and photolyzed at 350 nm to produce Bredt olefin protoadamantene 5 and 1‐noradamantyldiazomethane 8 in a 4:1 ratio. Encapsulated protoadamantene is stable for days at room temperature in (CD₃)₂SO/CD₃CN (t_1/2=5.5 days) and has a lifetime of several minutes in D₂O.     

内陆集装箱多式联运枢纽配置

根据集装箱内陆转运枢纽配置的影响因素,运用聚类分析方法确定备选节点,以总成本最小为目标建立集装箱货流分配模型.按重要度对备选节点进行排序,并将其逐一配置到网络中,求解模型,确定内陆集装箱枢纽的最佳配置方案.实例验证表明,该方案可以为内陆集装箱多式联运枢纽配置规划建设提供决策参考.     

5t集装箱配装计划优化程序

本文分析了5t 集装箱的配装情况,提出了配装优化的基本原理和模型,运用图论理论解决了检验两站集装箱车的径路问题,阐述了用计算机编制配装计划的实现过程.该程序用 FORTRAN—77语言编程,在 PDP—11/23机上调试通过.