Redesigning continental-scale monitoring networks

To address the problem of redesigning an existing continental-scale monitoring network, a method is given for optimally adding sites to a subregion of the continent so that both the mean relative error of estimation (estimate standard error divided by estimate) over the subregion and the standard deviation of the relative error estimate at the subregion's center are minimized.The method consists of two steps. First, the region is divided into disjoint subregions having homogeneous climatic/ecological characteristics. Then, for each subregion, optimal site locations are found by minimizing the dual objective function composed of the subregion's mean relative error and the standard deviation of a simulated relative error estimate at the subregion's center. The relative error with new sites is calculated by a moving window kriging algorithm that accounts for spatial trebd and heterogeneous spatial covariance through the use of data from the existing network.This method is applied to the problem of adding new sites to the U.S. National Atmospheric Deposition Program/National Trends Network using wet sulfate deposition data. It is found that for many of the subregions employed, on the order of a hundred new sites may be needed to reduce the subregion mean relative error by 5%. The subregion-center relative error standard deviation, however, can be reduced by about 50% in most subregions by the addition of no more than 10 sites.A subregion-based redesign method may be preferable to a region-based method when (a) network design goal priorities differ across subregions, and/or (b) network performance measures calculated over the entire region are insignificantly affected by the addition of a small number of new sites.     

滤筒式除尘器清灰性能研究

对 4种不同规格滤筒分别进行了清灰性能试验研究 ,试验结果表明滤筒夹角对滤筒清灰性能影响很大。当滤筒夹角小到一定程度时 ,在线清灰基本不起作用 ,必须采用离线清灰。试验还发现同一滤筒不同部位清灰效果不同 ,上部清灰效果最差 ,在此分析了其原因并提出改进措施。     

太阳风暴对短波电子装备性能的影响及应对措施

目的掌握太阳风暴对短波电子装备性能的影响及应对措施,为系统设计提供参考。方法分析太阳风暴的表现形式,并从作用距离、目标检测、定位精度等方面给出太阳风暴对短波超视距雷达、短波通信等装备的影响。结果电离层SID、电离层暴可造成短波通信中断,短波通信可用频段变窄。电离层强吸收可降低天波超视距雷达作用距离和目标定位精度,电子浓度、电离层虚高快速变化影响超视距雷达检测性能和定位精度,负相电离层暴使天波超视距雷达可用频段严重变窄。地球磁暴期间,电磁场突变产生的强电压和电流有可能烧毁用于天、地波超视距雷达的电子设备。电离层非规则现象对超视距雷达有严重影响。结论太阳风暴对电子装备性能有利有弊,要分别对待。系统设计时应充分考虑太阳风暴的影响,在出现太阳风暴时,采取针对性措施降低其影响。     

New estimates of down syndrome risks at chorionic villus sampling,amniocentesis, and livebirth in women of advanced maternal age from a uniquely defined population

Current measures of livebirth prevalence of Down syndrome are derived from data obtained up to 20 years ago, before the introduction of the prenatal diagnostic tests amniocentesis and chorionic villus sampling (CVS). For women aged 36–52 years, but who were not tested prenatally, we proposed to make a direct estimate of current livebirth prevalence of Down syndrome. We could also determine prevalence at the time of CVS and amniocentesis in women of the same age undergoing prenatal testing. Differences in these prevalences allow an estimation of the relative loss of Down syndrome during pregnancy. In Victoria, Australia, we identified 3041 women having CVS, 7504 having amniocentesis, and 13 139 having no test. Smoothed regression estimates of age-specific livebirth prevalence were found to be higher than in the early studies. The estimate of spontaneous loss was 17 per cent between the time of CVS and amniocentesis, and 18 per cent after the time of amniocentesis. The latter figure is lower than previous estimates and may be explained by a greater likelihood of a Down syndrome fetus surviving to be liveborn, given the modern approach to early obstetric intervention. These current risk estimates of livebirth may be useful updates for genetic counselling, but perhaps more importantly, may be used as precise maternal age-related risk figures, necessary in the design and implementation of prenatal screening programmes for Down syndrome.     

Overcoming barriers to the implementation of alternative fuels for road transport in Europe

The success of implementing alternative fuels for road transport depends on their cost, performance and reliability. This paper focuses on the use of natural gas and LPG, hydrogen and biofuels in Europe. A brief presentation is given of their technical development status, their market potential, and barriers to their implementation in various market segments. Some market barriers are common to many new technologies, and can be overcome through adequate policy measures at European level. Generally, a combination of policies is required, and a number of supporting measures increase their effectiveness. The following policies affecting energy use in transport are discussed: market incentives, policies targeting technology and vehicle efficiency, and overall system improvement.     

煤矿设计中环境保护篇章编制应注意的问题

依据建设项目环境保护设计规定中对各设计阶段提出的环境保护要求，结合目前矿区各阶段设计文件中涉及的环境保护篇章，分析了煤矿环境保护篇章编制过程中存在的问题，并提出相应的改进措施。     

Parallel Kinematic Machine Positioning Accuracy Assessment and Improvement

Although parallel kinematic machines potentially offer high force/torque capacity, structural rigidity, speeds, and dexterity, characterization of the first generation of hexapods has proven the need for improving the positioning accuracy before these new machines will be accepted for manufacturing applications. This paper proposes a systematic approach to assess the accuracy of a parallel kinematic machine subject to structural errors and then to effectively compensate for them. Analytical models were constructed for both the nominal and actual structures. Sensitivity analysis was performed, and it was determined-that of the 33 sources of error, only the six due to strut length deviations are significant. Simulations indicate that the accuracy of strut length calculations shows a discrepancy of at most ±4 micrometers. In summary, the simulation and preliminary experimental results show that the performance of parallel kinematic machines can be enhanced through error modeling and compensation.     

反应堆瞬发伽玛活化分析装置屏蔽性能研究

瞬发伽玛活化分析是一种高灵敏、非破坏的核分析技术。反应堆瞬发伽玛中子活化分析装置屏蔽设计是保护实验人员和提高装置分析灵敏度的重要保障。采用蒙特卡罗方法计算了中国先进研究堆瞬发伽玛活化分析装置的屏蔽性能和测量本底。利用公式修正的通过单晶铋过滤器的中子束流参数,使后续辐射水平计算结果更准确;采用分段-衔接的方法节省了计算时间。模拟结果显示,瞬发伽玛活化分析装置屏蔽性能满足辐射防护和低本底的要求,可为后续辐射防护措施的制定,实验人员辐射剂量优化以及同类装置屏蔽设计提供参考。     

Transitioning to sustainable production – part II: evaluation of sustainable machining technologies

This paper presents a case-study that highlights the importance of sustainable machining technologies in achieving sustainable development objectives. A technology evaluation was undertaken to understand the likely impacts of the use of technology on sustainability performance measures. The evaluation is more than an experimental method for supporting the design of technology and an instrument for supporting decision-making. It is also a tool for supporting technology policy and for encouraging its adoption and application in industry. More specifically, a sustainability evaluation of cryogenic and high pressure jet-assisted machining in comparison to conventional machining is examined. Sustainability performance measures refer to environmental impact, energy consumption, safety, personal health, waste management, and cost. The case-study refers to the machining of high-temperature Ni-alloy (Inconel 718). It is shown that tooling costs represent the major contribution to the overall production cost, which contradicts previous analyses, and that sustainable machining alternatives offer a cost-effective route to improving economic, environmental, and social performance in comparison to conventional machining.     

Multiobjective air pollution monitoring network design

The methodologies currently available to optimize the locations of air pollutant monitoring stations typically include a single pollutant and a single objective. In this paper, multiple objective functions are introduced that provide performance measures describing the spatial coverage of the network and its ability to detect violations of standards for multiple pollutants. An additional objective regarding the effect of data validity in the design is also considered. The objective functions are cast in a manner that permits considerable flexibility in the model formulation. The numerical difficulties associated with the formulation are discussed as are extensions of the basic framework. The basic model and its extensions have been applied to the design of a monitoring network for Tarragona, Spain.     

舰载电子设备可靠性与环境防护技术

分析海洋环境对舰载电子设备可靠性的影响,阐述抗恶劣环境技术与三防(防潮、防霉、防盐雾)设计总体方法,比较不同材料的环境防护性能,探讨密封性设计的技术方法。     

Understanding the effects of the system parameters of an ultrasonic cutting fluid application system for micro-machining

Tool wear in micro-milling poses a serious limitation to increased production rate, and atomized cutting fluids have been shown to be quite effective in increasing tool life in micro-milling operations. A new compact cutting fluid application system has been designed and developed based on ultrasonic atomization. In order to understand the effects of the system input parameters on system performance, two performance measures have been defined in terms of spray characteristics and experiments have been performed to evaluate the system according to the defined performance measures. Based on the experimental results, the system parameters can be adjusted to obtain the desired spray characteristics, and areas of improvement on the design have been identified.     

RAMS contribution to efficient waste minimisation and management

The significance of waste management systems in recent years increased due to the growing problems of waste management chains affecting the daily lives of millions of people and the impact on the environment. Several promising approaches have been developed in the past few years. One of them is the waste management system modelling using reliability, availability, maintainability and safety software. This paper analyses and evaluates this approach. The main goal is to provide quantitative forecasts for various performance measures of waste management systems. They include availability, downtimes, number of failures, and cost. Evaluation of these measures is important for optimal decision making. The system design should both maximise the system performance leading to cleaner processing and minimise the overall cost within the allowable constraints. The effectiveness of this methodology is demonstrated through a case study.     

仿生腿式地形自适应起落架构型与动力学分析

针对垂直起降飞行器在复杂地形环境下实现平稳着陆的难题,利用仿生学设计理念,以无人直升机为对象,设计了一种基于多连杆机构设计的仿生腿式起落架系统。通过对腿部机构进行运动学分析和动力学分析,建立相关模型,在此基础上,进行仿生腿式起落架的运动控制。首先,从无人直升机的着陆稳定性和承载能力出发,对仿生腿式起落架机械构型进行分析,并介绍了腿部各部分结构。然后,针对仿生腿腿部结构,通过几何法完成对腿部正运动学和逆运动学的求解,建立足端位置与驱动关节角度之间的映射关系。最后,基于运动学模型及四连杆运动学特性,对机体和单腿进行了动力学分析,并建模。通过建立的运动学和动力学模型,结合设计的起落架结构,完成动力学仿真,实现了仿生腿式起落架在复杂地形环境下的平稳着陆,验证了结构的合理性和模型的准确性。     

洁净手术部空调系统设计

简要介绍了手术室洁净技术的国内外发展历程与现状,并在此基础上,针对河北省三河市某医院的洁净手术部的工程建设,着重介绍了其工程概况和空调系统设计,包括空调系统的构成、设计参数、主要设备的特点及运行原理。在其工程实践的基础上提出了一些改进措施和建议。     

用油品的物理特性鉴别海面的溢油源

建立了用油品的物理特性鉴别海面溢油源的分析方法。主要对海面溢油风化过程中溢油的运动粘度和折射率的变化进行了探讨。结果表明 ,在所给出的多个油种的风化过程中 ,油种间的运动粘度变化存在着明显的差异。随着风化时间的延长 ,原油的运动粘度随着风化时间的延长而显著增加 ,重质燃料油虽略有递增却很不明显 ;轻质燃料油和润滑油的运动粘度均在缓慢地增加。润滑油和燃料油的折射率无明显的变化。运动粘度法鉴别溢油的准确度较高 ,其准确率可达 10 0 %。     

略论与电除尘器设计有关的几个问题

作者根据多年从事电除尘器工作的经验，提出了在设计、制造和调试中应充分考虑的诸如原始条件、设备参数选择、结构设计等影响电除尘器性能的各种因素，并从理论上进行分析和论证，以期通过讨论寻求最佳的设计方案和实践效果。     

论中央环境保护专项资金项目绩效评价指标体系构建

为定量、科学评价中央环境保护专项资金项目实施成效,本文基于逻辑框架方法,建立了中央环保专项资金项目的绩效评价模型,提出从投入、措施、产出、作用和影响等方面设计绩效评价指标。以模型为基础,结合中央环境保护专项资金项目绩效评价原则、项目管理需求和项目具体实施情况,构建了中央环境保护专项资金环境治理类项目绩效评价指标体系,包括资金投入与保障、项目实施与管理、项目产出、效益与可持续影响四类指数,每类指数下设4个指标,共16个评价指标。研究结论显示,基于逻辑框架法建立的绩效评价模型适用于分析不同类型环境保护项目的指标体系;所构建的指标体系对不同项目内容具有较好的适应性;本文研究思路可为相关研究提供有益借鉴。     

军用电子设备环境适应性设计有关问题探讨

军用电子设备的使用范围非常广,工作场所多种多样,设备的环境适应性问题比较突出。介绍了军用电子设备所面临的环境条件,分析了环境适应性设计步骤,结合设计经验,讨论了具体的环境适应性设计措施,包括温度控制措施;防振动抗冲击措施;电磁防护措施以及三防措施等。     

基于关键产品把控的舰船装备环境适应性设计对策分析方法

综合考虑舰船装备系统的复杂性和海洋环境的严酷性,提出了一种基于关键产品把控的舰船装备环境适应性设计对策分析方法.该方法在分析装备环境适应性设计基本要求的基础上,提出了按产品层次逐级进行环境适应性分析,根据其对上一级产品或整个装备系统功能的影响,层层剥离出环境适应性关键产品,通过识别环境适应性薄弱环节,消除环境适应性风险或隐患,建立了环境适应性设计关注点、环境要求、影响因素、薄弱环节、控制措施、具体方法等之间的映射关系,形成了环境适应性设计解决对策,建立了基于关键产品把控的舰船装备环境适应性设计对策分析方法,给出了方法应用示例.该方法为舰船以及其他装备开展环境适应性设计提供了一种可行的借鉴方法.