巴拿马运河对通航船舶的尺度视线和布置要求

介绍了巴拿马运河的航运和地理位置,运河对通航船舶的吃水限制和尺度限制,以及运河对通航船舶视线和布置的要求等,并简要介绍了巴拿马运河扩建工程。同时通过驾驶室视线图送审过程中遇到的一些问题,更清晰地阐明了规范要求。对规范规则的解读,以期给巴拿马级船舶设计提供参考。     

Biofuel futures in road transport – A modeling analysis for Sweden

First and second generation biofuels are among few low-carbon alternatives for road transport that currently are commercially available or in an early commercialization phase. They are thus potential options for meeting climate targets in the medium term. For the case of Sweden, we investigate cost-efficient use of biofuels in road transport under system-wide CO₂ reduction targets to 2050, and the effects of implementation of targets for an almost fossil-free road transport sector to 2030. We apply the bottom-up, optimization MARKAL_Sweden model, which covers the entire Swedish energy system including the transport sector. For CO₂ reductions of 80% to 2050 in the Swedish energy system as a whole, the results of the main scenario show an annual growth rate for road transport biofuels of about 6% from 2010 to 2050, with biofuels accounting for 78% of road transport final energy use in 2050. The preferred biofuel choices are methanol and biomethane. When introducing additional fossil fuel phase-out policies in road transport (−80% to 2030), a doubling of the growth rate to 2030 is required and system CO₂ abatement costs increases by 6% for the main scenario. Results imply that second generation biofuels, along with energy-efficient vehicle technologies such as plug-in hybrids, can be an important part of optimized system solutions meeting stringent medium-term climate targets.     

The impact of a congestion pricing exemption on the demand for new energy efficient vehicles in Stockholm

As governments seek to transition to more efficient vehicle fleets, one strategy has been to incentivize ‘green’ vehicle choice by exempting some of these vehicles from road user charges. As an example, to stimulate sales of energy efficient vehicles (EEVs) in Sweden, some of these automobiles were exempted from Stockholm’s congestion tax. In this paper the effect this policy had on the demand for new, privately-owned, exempt EEVs is assessed by first estimating a model of vehicle choice and then by applying this model to simulate vehicle alternative market shares under different policy scenarios. The database used to calibrate the model includes owner-specific demographics merged with vehicle registry data for all new private vehicles registered in Stockholm County during 2008. Characteristics of individuals with a higher propensity to purchase an exempt EEV were identified. The most significant factors included intra-cordon residency (positive), distance from home to the CBD (negative), and commuting across the cordon (positive). By calculating vehicle shares from the vehicle choice model and then comparing these estimates to a simulated scenario where the congestion tax exemption was inactive, the exemption was estimated to have substantially increased the share of newly purchased, private, exempt EEVs in Stockholm by 1.8% (±0.3%; 95% C.I.) to a total share of 18.8%. This amounts to an estimated 10.7% increase in private, exempt EEV purchases during 2008, i.e., 519 privately owned, exempt EEVs.     

轿车柴油化市场前景分析

汽车是能源消耗与环境污染的主要来源之一,而轿车又在汽车市场占据半壁江山,降低轿车能耗非常重要。柴油机较汽油机有着较大的节能环保的优势,在轿车中推行柴油化,必将对节能环保做出重要贡献。与世界发达国家相比,我国的轿车柴油化的水平还很低。虽然轿车柴油化已经具备一些有利的条件,但国内的油品和相关配套法规严重制约了柴油轿车的普及,我国的轿车柴油化还有很长的路要走。整车厂和主机厂应该积极开发轿车柴油化技术,更好地满足轿车柴油化的需求。     

关于电能计量装置的研究

DSP技术的迅速发展,为研制精确的电能计量装置提供了有力的技术支持。本装置就是通过采样电路采集到电网的电压和电流等数据,利用DSP快速处理数据的能力,对电压和电流采样数据进行FFT变换,得到各次谐波电压和电流的值,再根据谐波功率和电能计算方法,计算出电能值。     

增压空气驱动LiBr吸收式制冷复合循环的热力性能分析

提出吸收式制冷复合循环新模式，讨论了复合循环的热力计算。单效／双效复合循环有高低压2个发生器，高压发生器由高温级热源驱动，低压发生器由来自高压发生器的冷剂蒸汽与低温级热源联合驱动，实现高低温级热源的能量梯级利用。作为实例，对由高低温两级增压空气中冷器驱动的单效／双效复合循环进行了热力计算，并与单效循环和双效循环进行了热力性能比较。结果表明，复合循环的热力系数和制冷量均比单效循环高出15％，复合循环的余热利用量和制冷量分别高出双效循环153％和110％。     

探讨在区间设置无人值班通信机械室的设计要求

随着铁路运输的迅猛发展，特别是安全技术装备和信息技术的发展，介绍了在区间设置无人值班通信机械室的必要性，并对在区间设置无人值班通信机械室的一般要求、设计要求及工艺要求进行了探讨。     

Thermal design of automobile exhaust based thermoelectric generators: Objectives and challenges

The potential for thermoelectric power generation (via waste heat recovery onboard automobiles) to displace alternators and/or provide additional charging to a vehicle battery pack has increased with recent advances in thermoelectric material processing. In gasoline fueled vehicles (GFVs), about 40% of fuel energy is wasted in exhaust heat, while a smaller amount of energy (30%) is ejected through the engine coolant. Therefore, exhaust-based thermoelectric generators (ETEG) have been a focus for GFV applications since the late 1980s. The conversion efficiency of modern thermoelectric materials has increased more than three-fold in the last two decades; however, disputes as to the thermal design of ETEG systems has kept their overall efficiency at limited and insufficient values. There are many challenges in the thermal design of ETEG systems, such as increasing the efficiency of the heat exchangers (hot box and cold plate), maintaining a sufficient temperature difference across the thermoelectric modules during different operating conditions, and reducing thermal losses through the system as a whole. This paper focuses on a review of the main aspects of thermal design of ETEG systems through various investigations performed over the past twenty years. This paper is organized as follows: first, the construction of a typical ETEG is described. The heat balance and efficiency of ETEG are then discussed. Then, the third section of this paper emphasizes the main objectives and challenges for designing efficient ETEG systems. Finally, a review of ETEG research activities over the last twenty years is presented to focus on methods used by the research community to address such challenges.     

深圳地铁2号线工程再生制动能量吸收装置设置方案研究

研究目的：选择适合于深圳地铁2号线工程特点的再生制动能量吸收装置设置方案。 研究方法：针对再生制动能量吸收装置的几种设置方案，结合深圳地铁2号线工程实践，从车辆、环控、变电所、土建几个方面，分别对车载设置方案、地下变电所设置方案、地面变电所设置方案进行较为详细的分析比较。 研究结果：根据深圳地铁2号线沿线各车站现状，采用制动电阻地面通风散热的方案不具备工程可实施性，应采用车载制动电阻，并合理解决通风散热问题。 研究结论：指出了能否合理解决制动电阻的通风散热问题是本工程选择再生制动能量吸收装置设置方案的关键。     

海上示位标天线设计

示位标天线是确保反潜作战和海上搜救信息实时有效传输的关键。分析海上示位标天线的基本电参数,提出设计海上示位标天线的物理要求和技术要求,针对示位标使用频段设计两种适宜海上作业环境的示位标天线。