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121.
化石能源生产的生命周期清单不仅是开展化工产业及其产品生命周期分析的基础,也能阐明化石能源生产的基本环境行为.通过计算得到了2002年我国原煤、原油和天然气开采过程中直接相关的能源消耗和污染物排放,涉及到的污染物排放包括液态污染物、固体废弃物和CO2、SO2、NOx、CO、CH4、烟尘等气态排放物.  相似文献   
122.
大型露天矿在由山坡型转入深凹型开采后,随着运输条件的恶化,将单一的准轨铁路运输,改变为铁路—汽车联合运输,以延长铁路运输的服务年限,为此,需要解决提高电力机车运输性能、改造运输线路系统等问题。  相似文献   
123.
Gang Ning 《Electrochimica acta》2006,51(10):2012-2022
A generalized first principles based charge-discharge model to simulate the cycle life behavior of rechargeable Li-ion batteries has been developed. The model is based on loss of the active lithium ions due to the electrochemical parasitic reaction and rise of the anode film resistance. The effect of parameters such as depth of discharge (DOD), end of charge voltage (EOCV) and overvoltage of the parasitic reaction on the cycle life behavior has been quantitatively analyzed. The experimental results obtained at charge rate of 1 C, discharge rate of 0.5 C, EOCV of 4.0 V and DOD of 0.4 were used to validate the cycle life model. Good agreement between the simulations and the experiments has been achieved up to 1968 cycles. Simulation of a battery subjected to multiple cycling regimes has also been demonstrated.  相似文献   
124.
Atomic force microscopy (AFM) has been used to study the morphology and microstructure of an amine-cured epoxy before and after outdoor exposure. Measurements were made from samples prepared in an essentially CO2-free, H2O-free glove box and from samples prepared in ambient conditions. For those prepared in a CO2-free glove box, AFM imaging was conducted on (1) an unexposed air/coating surface, (2) an unexposed coating bulk, (3) an unexposed coating/substrate interface, and (4) a field exposed air/coating surface. For samples prepared in ambient conditions, only the unexposed air/coating surface was investigated. The same regions of the exposed samples were scanned periodically by the AFM to monitor changes in the surface morphology of the coating as UV exposure progressed. Small angle neutron scattering and Fourier transform infrared spectroscopy (FTIR) studies were performed to verify the microstructure and to follow chemical changes during outdoor exposure, respectively. The results have shown that amine blushing, which occurs only under ambient conditions, had a significant effect on the surface morphology and microstructure of the epoxy. The surface morphology of the samples prepared under CO2-free, dry conditions was generally smooth and homogeneous. However, the interface and the bulk samples clearly revealed a two-phase structure consisting of bright nodular domains and dark interstitial regions, indicating an inhomogeneous microstructure. Such heterogeneous structure of the bulk was in good agreement with results obtained by small angle neutron scattering of unexposed samples and by AFM phase imaging of the degraded sample surface. The relationship between submicrometer physical changes and molecular chemical degradation is discussed. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   
125.
采用提高温度加速老化与测定试样力学性能相结合的方法,依据挠性炸药(FEX-1)扯断永久变形随温度和时间的变化规律,预估该炸药在常温下的贮存寿命为11.8年。  相似文献   
126.
通过化学成份分析、金相的宏微观考察、Manson-Haferd参数对锥形接管持久寿命的估算,以及热应力的计算,对锥形接管的失效原因进行了分析,认为是由温差应力导致失效。所以应该充分注意高温构件保温措施的有效性,避免非正常温差应力的产生。  相似文献   
127.

Background

The use of surveys is becoming popular in the health care industry for acquiring information useful to the accomplishment of several studies. Besides their exploitation on a large scale for conducting epidemiological studies, surveys are being increasingly carried out on a narrower perspective through the administration of questionnaires aimed at assessing the quality of life perceived by patients or their clinical status during mid- or long-term treatments. This is useful for managing resources or optimizing and individualizing treatments.

Objectives

This paper describes Gquest, a platform for modeling, generating and administering questionnaires through mobile devices such as smartphones or tablets. Gquest was motivated by the need of administering questionnaires during home treatments, albeit its applicability is rather general. The main requirement was to have a very simple, clean and easy to use platform able to support (a) physicians in the design and delivery of questionnaires and (b) outpatients in sending self-recorded outcomes to the clinical staff.

Methods

Gquest has two basic components. The first one is a model devised for representing questionnaires which is extremely flexible. It allows the generation of questions and answers of different types, supports adaptivity in the dialog with the user and enforces simple consistency rules for checking his input. The second component is an application able to run instances of those questionnaires. It downloads questionnaires over the air in terms of XML files from a server and stores them locally into the mobile repository. Questionnaires become then available to the user, who in our case is a patient or one of his relatives. The user can select which one to fill-in, according to his needs and/or the specific treatment protocol. The selected questionnaire may be filled-in all at once or be completed in subsequent steps over time since any input provided is persisted on a local database. Finally, when a questionnaire is closed all the answers are transparently synchronized to a server for further evaluation or statistical purposes.

Results

The platform has been exploited and tested in two medical domains where questionnaires have very different purposes; a quality of life pilot survey involving patients with atrial fibrillation within the EU-funded project MobiGuide, and an investigation of the users’ needs during the requirements elicitation phase of a telemedicine project for the safe discharge of fragile patients.

Conclusions

Gquest proved to be a suitable tool for dealing with a wide variety of question types and has been positively accepted by the patients enrolled in the pilot study.  相似文献   
128.
本文叙述有关国内外自动化仪表在工业生产流程中的可靠性,维修性及安全性。  相似文献   
129.
LiNi1/3Co1/3Mn1/3O2 cathode materials have been coated with Al2O3 nano-particles using sol-gel processing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-prepared Al2O3 nano-particles was indexed to the cubic structure of the γ-Al2O3 phase and had an average size of ∼4 nm. The XRD showed that the structure of LiNi1/3Co1/3Mn1/3O2 was not affected by the Al2O3 coating. However, the Al2O3 coatings on LiNi1/3Co1/3Mn1/3O2 improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO2-coated LiNi1/3Co1/3Mn1/3O2 cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al2O3-coated LiNi1/3Co1/3Mn1/3O2 compared to uncoated LiNi1/3Co1/3Mn1/3O2.  相似文献   
130.
提出一种基于"放大因子"、采用二维平面单元模拟三维实体动态工况的计算疲劳的方法,对某矿车减速机齿轮系统进行疲劳分析,得到太阳轮、行星轮和扭力管在不同抗拉强度下的疲劳寿命.结果表明:太阳轮和扭力管最易发生疲劳破坏;齿轮寿命对抗拉强度的依赖性较敏感;得出的齿轮系统热处理后的抗拉强度建议值能为设计提供参考,且该方法能大大提高计算效率.  相似文献   
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