基于铁路货运系统装卸业务利润率的研究

装卸业务是铁路货物运输的重要保障环节。同时装卸作为最重要的货运两端业务,成本在运输总支出中占有最大的比重,加强装卸成本管理,提高装卸利润率是实现货运经营目标的重要方面。提升货运系统的装卸成本管理水平,首先在装卸作业组织上,使用变动成本法合理规划装卸作业方式即路工装卸或业务外包,其次是对路工装卸的成本支出项目使用精细化管理,提高装卸利润率。

《清夜钟》作者非陆云龙考

路工先生关于《清夜钟》作者为陆云龙的判断存在多处疏漏,确凿的四条证据证明陆云龙并非《清夜钟》作者,从《型世言》、《清夜钟》、《魏忠贤小说斥奸书》三书中共同存在的吴语方言,只能推测出他是江浙文人。

基于城轨车辆升级扩容的信号系统方案研究

描述典型CBTC系统,从车辆扩容的角度分析信号系统的各个子系统的影响和设计方案,对项目初期的信号系统设计提出建议;结合项目实际情况,明确车辆升级扩容后会影响信号系统设计的车辆参数,结合车辆参数进行信号系统方案的研究,同时从信号系统的角度提出对车辆尺寸、设备安装位置、牵引制动特性、接口总线等各个设计的需求,评估信号系统可接受的车辆参数,为车辆方的车辆设计及信号系统的技术方案提供设计参考。

Numerical simulation of dynamic pore pressure in asphalt pavement

For studying the driving role of dynamic pressure in water-induced damage of asphalt pavement, based on the fast Lagrangian finite difference method and Biot dynamic consolidation theory, fluid-solid coupling analysis of the pavement is conducted considering asphalt mixtures as porous media. Results reveal that the development and dissipation of the dynamic pore pressure are coinstantaneous and this makes both the positive and negative dynamic pore pressure and seepage force alternate with time. Repetitive hydrodynamic pumping and sucking during moisture damage is proved. The dynamic pore pressure increases with vehicle velocity. Effective stress and deflection of pavement decrease due to the dynamic pore water pressure. However, the emulsification and replacement of the asphalt membrane by water are accelerated. The maximum dynamic pore pressure occurs at the bottom of the surface course. So it is suggested that a drain course should be set up to change the draining condition from single-sided drain to a two-sided drain, and thus moisture damage can be effectively limited.

Mechanics analysis of vehicle bumping at approach slabs with superelevation

In order to analyze the pavement stress caused by vehicle bumping at an approach slab, a simplified four-wheeled bi- axle vehicle-moving model is proposed. The effect of damping and vibration reduction in the process of vehicle-moving is not considered. Based on the position change of vehicle wheels at the approach slab, the vehicle dynamic vibration equations are summarized. Meanwhile, the undetermined coefficients of the vibration equations are obtained using the boundary and initial conditions of the vehicle. The analytical motion solutions of rear and front wheels at different stages are concluded. Consequently, a four-wheeled vehicle model is developed and vibration equations are provided, which can be used to analyze the impact of complicated stress on pavement. The results show that the excessive stress and stress concentration will occur at the approach slab, and it needs to be strengthened.

EFFECT OF TOOL-PATH ON MILLING ACCURACY UNDER CLAMPING

To resolve the deformation problem for thin-walled aero-parts in the actual production, this paper simulates the effect of the tool-path on the machining accuracy of the thin-walled frame. The frame is shaped in the part milling under a given clamping condition by using the three-dimensional finite element method （FEM）. Result shows that the sidewall deformation has a big difference if only the tool-path changes. When the tool-path from the outside to the inside is used, the machining deformation is smaller than another three kinds of toolpaths. Simulation results are compared with experimental data, and the correctness of the simulation is verified.Reasonable processing paths can be found by FEM.

Analysis on fatigue cracking for asphalt surface layers based on field cores

Field cores from typical cracking locations were tested by the semi-circular bending test and the digital image correlation method to evaluate the anti-fatigue performance of different asphalt pavements. Test results were analyzed by different fatigue models. Causes of fatigue cracking for different pavement sections were determined by extraction and sieving test results. It is found that the ranking （from high to low） in terms of the anti-fatigue performance for field cores is the crumb rubber modified asphalt mixture, densegraded modified asphalt mixture, continuous graded asphalt treated base, gap-graded stone asphalt concrete, and half open-graded asphalt macadam. Compared with the half opengraded asphalt macadam, the fatigue life of the crumb rubber modified asphalt mixture improves by 2. 0 to 3. 8 times. Fatigue lives of different mixtures and distress ratios of actual pavements can be accurately predicted by the dissipated energy density ratio. Causes of fatigue cracking vary with mixture types.

Integrated circuit for single channel neural signal regeneration

Based on the 4-channel neural signal regeneration system which is realized by using discrete devices and successfully used for in-vivo experiments on rats and rabbits, a single channel neural signal regeneration integrated circuit （IC）is designed and realized in CSMC ＇ s 0. 6 μm CMOS （ complementary metal-oxide-semiconductor transistor ） technology. The IC consists of a neural signal detection circuit with an adjustable gain, a buffer, and a function electrical stimulation （FES） circuit. The neural signal regenerating IC occupies a die area of 1.42 mm × 1.34 mm. Under a dual supply voltage of ±2. 5 V, the DC power consumption is less than 10 mW. The on-wafer measurement results are as follows： the output resistor is 118 ml）, the 3 dB bandwidth is greater than 30 kHz, and the gain can be variable from 50 to 90 dB. The circuit is used for in-vivo experiments on the rat＇ s sciatic nerve as well as on the spinal cord with the cuff type electrode array and the twin-needle electrode. The neural signal is successfully regenerated both on a rat＇ s sciatic nerve bundle and on the spinal cord.

Monolithically Integrated Optoelectronic Receivers Implemented in 0.25μm MS/RF CMOS

A monolithically integrated optoelectronic receiver is presented. A silicon-based photo-diode and receiver circuits are integrated on identical substrates in order to eliminate the parasitics induced by hybrid packaging. Implemented in the present deep sub-micron MS/RF （mixed signal, radio frequency） CMOS,this monolithically OEIC takes advantage of several new features to improve the performance of the photo-diode and eventually the whole OEIC.

CMOS Quadrature Modulator and Up-Conversion Mixer for 802.11a Wireless LAN Systems

A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the upconversion mixer to improve its gain and increase the voltage swing. The measurement results show that the input P1dB achieves -3.6dBm, the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.

施工中发生的路基问题分析

通过一些工程实例,论述了由于工程地质条件的复杂性,地质调查不详细,未能作认真的观察分析,以及施工中轻视质量,造成了一些路基质量问题。

Design and Realization of CPW Circuits Using EC-ANN Models for CPW Discontinuities

Novel accurate and efficient equivalent circuit trained artificial neural-network （EC-ANN） models,which inherit and improve upon EC model and EM-ANN models＇ advantages,are developed for coplanar waveguide （CPW） discontinuities. Modeled discontinuities include ： CPW step, interdigital capacitor, symmetric cross junction, and spiral inductor, for which validation tests are performed. These models allow for circuit design, simulation, and optimization within a CAD simulator. Design and realization of a coplanar lumped element band pass filter on GaAs using the developed CPW EC-ANN models are demonstrated.

DEPTH PREDICTION OF RAIN WATER ON ROAD SURFACE BASED ON ARTIFICIAL NEURAL NETWORK

A model based on the non-linear artificial neural network （ANN） is established to predict the thickness of the water film on road surfaces. The weight and the threshold can be determined by training test data, and the water film thickness on the road surface can be accurately predicted by the empirical verification based on sample data. Results show that the proposed ANN model is feasible to predict the water film thickness of the road surface.

Challenges to Data-Path Physical Design Inside SOC

Previously,a single data-path stack was adequate for data-path chips,and the complexity and size of the data-path was comparatively small.As current data-path chips,such as system-on-a-chip (SOC),become more complex,multiple data-path stacks are required to implement the entire data-path.As more data-path stacks are integrated into SOC,data-path is becoming a critical part of the whole giga-scale integrated circuits (GSI) design.The traditional physical design methodology can not satisfy the data-path performance requirements,because it can not accommodate the data-path bit-sliced structure and the strict performance (such as timing,coupling,and crosstalk) constraints.Challenges in the data-path physical design are addressed.The fundamental problems and key technologies in data-path physical design are analysed.The corresponding researches and solutions in this research field are also discussed.

A Practical Backside Technology for Indium Phosphide MMICs

A wet etching process for backside via holes suitable for use on InP MMICs technologies is developed for indium phosphide substrate.PMMA is used to mount InP wafer onto glass carrier.Spattered Ta film is utilized as etch mask.HCl+H 3PO 4 solution realised a etch until a depth of 100μm.It is demonstrated that the wet etching backside process is controllable with large latitudes.

Incremental Placement Algorithm for Standard-Cell Layout

A new algorithm W ECOP is presented to effect incremental changes on a standard cell layout automatically.This algorithm deals with cell inserting and cell moving based on rows instead of on cells as most placement algorithms usually do.An integer programming problem is formulated to minimize the adjustment on the initial placement and a heuristic method is presented to search for a shifting path so as to optimize the wirelength.Test of W ECOP on a group of practical test cases shows that the algorithm can successfully accomplish incremental placement with good quality and high speed.

Economic Globalization: An Irresistible Trend Despite Imperfections

The world is entering into a new era of economic globalization. Realizing the benefits of globalization depends on a host of realistic conditions including technology and infrastructure, geopolitical pattern and the structure of market power, and international institutional arrangements, i.e., the global governance structure, among others. In this new era of economic globalization, international competition boils down to the ＂good governance＂ of countries rather than the use of force and hegemonism. Most importantly, a country must promote the vibrancy of innovation in order to stay competitive and creative. In this sense, China＇s position in the new era of economic globalization hinges upon its transition from being the ＂leader of world economic growth＂ to being a future ＂leader of good governance and vibrancy. ＂ Interests of various economies become interlocked, intertwined and overlap. Despite the inevitability of conflicts and frictions, more inclusive and balanced global development serves the interests of most nations. For great powers with extended boundaries of interests across the world, the maintenance of the new balance of power in economic globalization is consistent with their respective national interests. Hence, in the new era of economic globalization characterized by the inevitability of intricate interests and inevitable conflicts, the world is likely to be more peaceful, competitive and inclusive than any previous age of economic globalization.

High-altitude gastrointestinal bleeding:An observation in Qinghai-Tibetan railroad construction workers on Mountain Tanggula

AIM: To investigate the gastrointestinal bleeding (GIB) in people from lowland to high altitude and in workers on Mountain Tanggula and its causes as well as treatment and prophylaxis.METHODS: From 2001 to October 2003, we studied GIB in 13 502 workers constructing the railroad on Mountain Tanggula which is 4905 m above the sea level. The incidence of GIB in workers at different altitudes was recorded. Endoscopy was performed when the workers evacuated to Golmud (2808 m) and Xining (2261 m). The available data on altitude GIB were analyzed.RESULTS: The overall incidence of GIB was 0.49% in 13 502 workers. The incidence increased with increasing altitude. The onset of symptoms in most patients was within three weeks after arrival at high altitude. Bleeding manifested as hematemesis, melaena or hematochezia, and might be occult. Endoscopic examination showed that the causes of altitude GIB included hemorrhage gastritis, gastric ulcer, duodenal ulcer, and gastric erosion. Experimental studies suggested that acute gastric mucosal lesion (AGML) could be induced by hypoxic and cold stress, which might be the pathogenesis of altitude GIB. Those who consumed large amount of alcohol, aspirin or dexamethasone were at a higher risk of developing GIB. Persons who previously suffered from peptic ulcer or high-altitude polycythemia were also at risk of developing GIB. Early diagnosis, evacuation, and treatment led to early recovery. CONCLUSION: GIB is a potentially life threatening disease, if it is not treated promptly and effectively. Early diagnosis, treatment and evacuation lead to an early recovery. Death due to altitude GIB can be avoided if early symptoms and signs are recognized.

Improving Characteristics of Integrated Switched-Capacitor DC-DC Converter by CMOS Technology

An integrated 3.3V/1.2V SC DC-DC converter operating under 10MHz with a fixed duty radio of 0.5 is presented.To improve the output current of the converter,CMOS technology is adopted to fabricate the switching devices,and mutually compensatory circuitry technology is also employed to double the output current furthermore.The simulation results using Hspice simulation software,show that the output currents of a single unit circuit and two unit circuits connected in a mutually compensatory manner of the improved converter is about 12.5mA and 26mA,respectively.The power conversion efficiency of the mutually compensatory circuit can amount to 73%,while its output voltage ripple is less than 1.5%.The converter is fabricated in standard Rohm 0.35μm CMOS technology in Tokyo University of Japan.The test result indicates that the output current of 9.8mA can be obtained from a single unit circuit of the improved converter.

Mechanics model of additional longitudinal force transmission between bridges and continuously welded rails with small resistance fasteners

A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement (among) the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.