Airport and airlines competition: Incentives for vertical collusion

This paper develops a model of airport and airline competition in a three-stage game. We analyse incentives for vertical collusion between one airport and one airline that compete with another airport and another airline, by means of static and dynamic games. We find that incentives for collusion exist when airports and airlines have different market sizes and, under certain conditions, also when secondary airports and low cost airlines compete with main airports and full service airlines.     

刚性汽车的纵向极限稳定性分析

通过对刚性汽车进行受力分析,得到了刚性汽车发生纵翻的条件,并对汽车的纵向极限稳定性进行了分析,指出了提高汽车纵向稳定性的措施。     

骨髓间充质干细胞对5/6肾切除大鼠肾脏损伤时Bcl-2、Bax表达的影响

目的探讨骨髓间充质干细胞(BMSCs)移植对5/6肾切除大鼠肾损伤的保护作用,观察BMSCs对肾组织Bcl-2、Bax表达的影响。方法将雄性SD大鼠BMSCs用PKH26标记后注入受体雌性SD大鼠体内。40只受体雌性SD大鼠随机分为4组(n=10):假手术组、5/6肾切除+DMEM-F12组(模型组)、5/6肾切除+贝那普利组(对照组)、5/6肾切除+BMSCs组(干细胞组)。60d后观察肾功能改变;免疫组化法检测Bcl-2和Bax的表达,并观察PKH26标记的BMSCs在受体大鼠肾脏的分布情况。结果假手术组肾功能明显好于其余各组(P<0.05),对照组和干细胞组肾功能明显好于模型组(P<0.05);模型组Bcl-2、Bax表达及Bcl-2/Bax比值明显高于其余各组(P<0.05),干细胞组Bcl-2和Bax表达明显高于对照组(P<0.05)。5/6肾切除后第60d可见标记的BMSCs定位于肾组织中。结论外源性BMSCs可减少Bcl-2和Bax蛋白表达,下调Bcl-2/Bax比值,减少肾组织细胞凋亡,从而有利于肾功能的早期恢复。     

城市道路交叉口竖向设计方法及实例分析

文章介绍了道路平面交叉口竖向设计的原则和一般形式,阐述了常用的交叉口竖向设计方法及适用性,并结合工程设计实例,对比分析了两套拟定交叉口竖向设计方案的优缺点,得出最优方案,为今后城市道路交叉口竖向设计提供参考。     

Mesoscale subduction at the Almeria–Oran front: Part 1: Ageostrophic flow

This paper presents a detailed diagnostic analysis of hydrographic and current meter data from three, rapidly repeated, fine-scale surveys of the Almeria–Oran front. Instability of the frontal boundary, between surface waters of Atlantic and Mediterranean origin, is shown to provide a mechanism for significant heat transfer from the surface layers to the deep ocean in winter. The data were collected during the second observational phase of the EU funded OMEGA project on RRS Discovery cruise 224 during December 1996. High resolution hydrographic measurements using the towed undulating CTD vehicle, SeaSoar, traced the subduction of Mediterranean Surface Water across the Almeria–Oran front. This subduction is shown to result from a significant baroclinic component to the instability of the frontal jet. The Q-vector formulation of the omega equation is combined with a scale analysis to quantitatively diagnose vertical transport resulting from mesoscale ageostrophic circulation. The analyses are presented and discussed in the presence of satellite and airborne remotely sensed data; which provide the basis for a thorough and novel approach to the determination of observational error.     

桥上CRTSⅡ型板式无砟轨道底座张拉纵连模拟分析

根据桥上CRTSⅡ型板式无砟轨道结构特点,建立桥上CRTSⅡ型板式无砟轨道底座施工全过程的有限元计算模型,分6个施工步骤分析底座从浇筑、张拉再到锁定整个过程中的受力及变形,研究表明:张拉前需确定底座锁定板温,以控制底座温度变化幅度;张拉时整个断面需均匀张拉,避免出现因应力集中而导致混凝土拉裂,当底座温差较大时,必须每隔24 h重复张拉1次,直到达到最终的张拉量;张拉完成后,BL2后浇带必须待混凝土浇筑段内应力均衡后方能浇筑。     

油润滑船舶尾管尾密封装置改装实践

对油润滑船舶尾管尾密封装置的结构、工作原理、使用材料等方面进行了分析，并就公司拖轮的尾管尾密封装置改装实践提出可行方案，取得了较好的效果。     

垂直发射舰炮综述

本文简述了垂直发射舰炮研究的背景、总体方案及各机构的构想，如舰炮总体、自动弹药仓、模块化炮管、装填系统等。分析了垂直发射舰炮的特点、关键技术和必须重点研究的相关问题。     

A trace metal (Pb, Cd, Zn, Cu) balance for surface waters in the eastern Gotland Basin, Baltic Sea

Trace metal inventories and transboundary fluxes were estimated for the surface waters of the eastern Gotland Basin, and a mass balance for this water body was derived.The study area was delineated by a box which bordered vertically by the sea surface and the halocline and horizontally by the coast of Gotland and the coast of Latvia/Lithuania. For the calculation of the trace metal inventories in the box, a high-resolution sampling was carried out during different seasons. Additional sediment trap studies were performed to calculate the vertical particulate trace metal fluxes through the halocline.The following transboundary fluxes have been estimated: (a) atmospheric input of trace metals; (b) lateral transport from adjacent bodies of surface water; (c) diapycnal fluxes of dissolved trace metals at the halocline; (d) sinking of trace metals, associated with particles, through the halocline, (e) vertical advection through the halocline.The lateral transport into and out of the surface box is important for the metals (Cd, Cu, Zn) with “nutrient-like” behaviour. For particle reactive elements like lead, vertical sedimentation and lateral transport out of the box as much as atmospheric input and lateral input into the box are in the same order of magnitude. Turbulent diapycnal mixing plays a minor role compared to the advective fluxes.The estimated range for the residence times for the region under investigation are  0.5–1.3 years for Pb;  2–11 years for Zn,  7–36 years for Cd and 42–89 years for Cu. This demonstrates that the system reacts very fast for particle reactive elements like Pb, while for copper sedimentation processes are not the preferential sink and can be neglected.     

舰载导弹垂直发射系统综述

垂直发射系统目前已成为海军舰艇应用最为广泛的导弹发射系统。本文分析了垂直发射系统的优点，介绍了几种现役的垂直发射系统和新型垂直发射系统的研制状况。