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伴随卫星的燃料-时间优化回收
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作者 张健 戴金海 《宇航学报》 EI CAS CSCD 北大核心 2007年第1期167-170,208,共5页
伴随卫星回收是伴星应用中的一项主要技术。航天任务需求对伴星回收问题不仅提出了最省燃料要求,而且提出了最小时间要求。本文设计了一条稳定的燃料-时间优化回收轨道。从相对运动的Hill方程出发,给出伴星回收问题描述,阐述回收轨道设... 伴随卫星回收是伴星应用中的一项主要技术。航天任务需求对伴星回收问题不仅提出了最省燃料要求,而且提出了最小时间要求。本文设计了一条稳定的燃料-时间优化回收轨道。从相对运动的Hill方程出发,给出伴星回收问题描述,阐述回收轨道设计思想及稳定回收条件,提出一种有效的螺旋式回收策略,探讨参数确定方法,并对回收轨道的特点和稳定性进行分析,最后研究了燃料消耗量与回收时间及初始相位的关系。仿真结果表明,利用螺旋回收策略,可以保证伴随卫星快速、稳定回收,且能在燃料消耗量与回收时间之间寻求最佳折衷。 展开更多
关键词 伴随卫星 相对轨道控制 燃料-时间优化
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某小型天然气增压发动机燃料喷射时间对性能的影响研究 被引量:1
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作者 朱云峰 史程中 +3 位作者 杨陈 尹建东 沈源 王瑞平 《小型内燃机与车辆技术》 2018年第2期82-84,96,共4页
在小型天然气发动机上,燃料喷射时间对发动机的燃油消耗率及HC、NOx排放有很大的影响。每个工况都存在一个最佳的燃料喷射时间,标定过程中,每个工况匹配最佳的燃料喷射时间,可改善发动机的燃烧特性,在一定程度上提高发动机的燃油经济性... 在小型天然气发动机上,燃料喷射时间对发动机的燃油消耗率及HC、NOx排放有很大的影响。每个工况都存在一个最佳的燃料喷射时间,标定过程中,每个工况匹配最佳的燃料喷射时间,可改善发动机的燃烧特性,在一定程度上提高发动机的燃油经济性及动力性,降低排放。 展开更多
关键词 小型天然气发动机 燃料喷射时间 燃烧特性
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航天器近距离变轨能量时间关系研究
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作者 张琪新 夏焕军 闵海波 《计算机工程与应用》 CSCD 2012年第24期201-205,共5页
随着航天任务需求的多样化,对航天器轨道转移问题不但提出了最省燃料要求,还提出了最小时间要求。主要研究了航天器近距离双脉冲变轨燃料和时间最优问题,基于线性化C-W方程,推导了在轨服务器在双冲量变轨时的特征速度,以时间-燃料为指... 随着航天任务需求的多样化,对航天器轨道转移问题不但提出了最省燃料要求,还提出了最小时间要求。主要研究了航天器近距离双脉冲变轨燃料和时间最优问题,基于线性化C-W方程,推导了在轨服务器在双冲量变轨时的特征速度,以时间-燃料为指标构造了加权模型,分析单一和混合指标情况下对系统的影响后,得到了混合指标下时间和能量关系,通过设计分布估计算法,找到最优能量和相应的转移时间,使得燃料和时间的加权和最小,实现近距离变轨最优指标的精确数值模拟。从数值结果的对比分析中得出了一些有意义的结论,可供下一步研究参考。 展开更多
关键词 航天器轨道转移 燃料时间 双冲量变轨 分布估计算法
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使用大亚湾核电站乏燃料的池式堆概念核设计 被引量:2
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作者 蔡德昌 王侃 姚增华 《核动力工程》 EI CAS CSCD 北大核心 2004年第5期385-389,共5页
计算了使用大亚湾核电站乏燃料的池式堆所需的组件数,分析了135Xe,149Sm和241Pu对反应性的影响及乏燃料冷却时间与循环长度的关系,指出抽掉含钆棒能够增加循环长度。设计了使用大亚湾核电站乏燃料的池式堆堆芯布置方案。从核设计的角度... 计算了使用大亚湾核电站乏燃料的池式堆所需的组件数,分析了135Xe,149Sm和241Pu对反应性的影响及乏燃料冷却时间与循环长度的关系,指出抽掉含钆棒能够增加循环长度。设计了使用大亚湾核电站乏燃料的池式堆堆芯布置方案。从核设计的角度进一步阐明了这种堆型的可实现性。 展开更多
关键词 燃料池式堆 循环长度 水铀比 燃料冷却时间
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车联网环境下考虑续航时间约束的公交车辆行车计划编制 被引量:2
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作者 史桂红 《南通大学学报(自然科学版)》 CAS 2017年第2期6-11,共6页
公交车辆的行车计划智能化编制是"互联网+交通"和公交优先战略的重要体现,也是提高公交吸引力和缓解城市交通拥堵的有效途径.在对现有行车计划编制模型进行研究的基础上,提出了燃料续航时间约束条件下的多场站行车计划编制模... 公交车辆的行车计划智能化编制是"互联网+交通"和公交优先战略的重要体现,也是提高公交吸引力和缓解城市交通拥堵的有效途径.在对现有行车计划编制模型进行研究的基础上,提出了燃料续航时间约束条件下的多场站行车计划编制模型,并依托车联网环境的信息交互,探讨了续航时间约束下的车辆调度问题与背包问题的对应关系,提出了一种应用贪婪算法求解该问题的方法.最后,通过算例验证了模型的有效性,并对比了参与调度车辆数目与续航时间约束对结果的影响.分析结果表明:在续航时间约束不变的情况下,增加调度车辆的数目,可以降低空驶时间和执行里程,但车辆执行时间的波动性增大,车辆间运行公平性降低;增加续航里程可以增加车辆的使用频率,提高车辆的使用效率.公交车辆的行车计划编制不仅要考虑费用,还需考虑车辆接受班次任务的均衡性,宜根据不同的续航时间约束条件来管理调度车辆. 展开更多
关键词 公交车辆 车联网 行车计划编制 燃料续航时间.
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环氧丙烷点火的光谱研究 被引量:2
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作者 胡栋 袁长迎 +3 位作者 李萍 程新路 刘锦超 孙珠妹 《高压物理学报》 CAS CSCD 北大核心 2003年第3期169-172,共4页
利用多种光谱技术 ,提出了一种确定燃料冲击点火延迟时间的新方法。用这种方法所获得的实验值比国内外常用光电二极管 (峰值波长约在 80 0nm)方法的所测值更接近实际值。环氧丙烷受冲击后 ,反应中间产物出现的时间是不同的 ,辐射强度也... 利用多种光谱技术 ,提出了一种确定燃料冲击点火延迟时间的新方法。用这种方法所获得的实验值比国内外常用光电二极管 (峰值波长约在 80 0nm)方法的所测值更接近实际值。环氧丙烷受冲击后 ,反应中间产物出现的时间是不同的 ,辐射强度也不同。在冲击波作用下 ,基团出现的顺序便可确定 ,它们依次为O、CH2 O、C2 、CH、CH3O、CO2 、H2 O等 。 展开更多
关键词 环氧丙烷 点火 光谱分析 谱仪技术 燃料冲击点火延迟时间
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格栅类通透性吊顶对水喷淋控火性能影响的实验研究 被引量:8
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作者 高兵 姚斌 《火灾科学》 CAS CSCD 2008年第4期244-249,共6页
通过实验研究了格栅类通透性吊顶对水喷淋控火性能的影响,并利用燃料燃尽时间来计算控火有效性因子来量化这种影响。研究结果表明:格栅会降低水喷淋控火性能,与格栅类吊顶形式、喷头安装高度和工作压力流量有关。在确定的吊顶形式和尺寸... 通过实验研究了格栅类通透性吊顶对水喷淋控火性能的影响,并利用燃料燃尽时间来计算控火有效性因子来量化这种影响。研究结果表明:格栅会降低水喷淋控火性能,与格栅类吊顶形式、喷头安装高度和工作压力流量有关。在确定的吊顶形式和尺寸下,存在着对控火性能影响最大的喷头安装高度。在实际工程应用中应根据具体格栅特性,合理设计喷头安装高度,以降低格栅的不利影响,保证水喷淋的控火有效性。 展开更多
关键词 水喷淋 格栅吊顶 控火有效性 燃料燃尽时间 喷头安装高度
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Optimization of dilute acid hydrolysis of Enteromorpha 被引量:1
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作者 冯大伟 刘海燕 +2 位作者 李富超 姜鹏 秦松 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第6期1243-1248,共6页
Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydroly... Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydrolysis of Enteromorpha using acids that are typically used to hydrolyze biomass: H2SO4, HC1, H3PO4 and C4H404 (maleic acid). 5%(w/w) Enteromorpha biomass was treated for different times (30, 60, and 90 min) and with different acid concentrations (0.6, 1.0, 1.4, 1.8, and 2.2%, w/w) at 121~C. H2SO4 was the most effective acid in this experiment. We then analyzed the hydrolysis process in H2SO4 in detail using high performance liquid chromatography. At a sulfuric acid concentration of 1.8% and treatment time of 60 min, the yield of ethanol fermentable sugars (glucose and xylose) was high, (230.5 mg/g dry biomass, comprising 175.2 mg/g glucose and 55.3 mg/g xylose), with 48.6% of total reducing sugars being ethanol fermentable. Therefore, Enteromorpha could be a good candidate for production of fuel ethanol. In future work, the effects of temperature and biomass concentration on hydrolysis, and also the fermentation of the hydrolysates to ethanol fuel should be focused on. 展开更多
关键词 ENTEROMORPHA acid hydrolysis ethanol fermentable sugars
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Optimization of Bacterial Doses and Incubation Time on Bio-Ehanol Fermentation of Nipah (Nypa fruticans) for Biofuel Energy
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作者 Wiludjeng Trisasiwi Ari Asnani Retna Setyawati 《Journal of Life Sciences》 2011年第12期1022-1029,共8页
Nipah (Nypafruticans) is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1) to determine the optimum ... Nipah (Nypafruticans) is a species of palm trees that grows in mangroves environment near the sea shore. Nipah is potential to produce biofuel energy. The purposes of this research were 1) to determine the optimum bacterial concentration for fermentation to produce high concentration of bio-ethanol, and 2) to determine the optimum incubation time for fermentation to produce high concentration of bio-ethanol. The research had been conducted from June until November 2009 using nipah sap as the substrate and Saceharomyces cerevisiae as a fermentation starter. The experimental design used was a randomized block design (RBD). Factors tested were starter concentration (5%, 7.5%, 10%) and incubation time (2, 4, 6 days). The variables observed were concentration of reducing sugar, total microorganism (CFU/mL), and bio-ethanol production. The results showed that the highest yield of bio-ethanol (8.98%) was produced with 7.5% of starter concentration and 6 days of incubation time. 展开更多
关键词 BIO-ETHANOL bacterial concentration incubation time Nypafruticans Saccharomyces cerevisiae
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Preparation and Characterization of Indium Doped Tin Oxide (ITO) via a Solvothermal Method
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作者 Anh Khuong Quoc Nguyen Van Thi Thanh Ho 《Journal of Environmental Science and Engineering(B)》 2016年第8期379-384,共6页
Tin-doped Indium Oxide (ITO) has been successfully prepared via solvothermal method with a mixture of Indium(Ill) acetylacetonate and Tin(IV) bis(acetylacetonate)dichioride in oleyamine solvent under the condi... Tin-doped Indium Oxide (ITO) has been successfully prepared via solvothermal method with a mixture of Indium(Ill) acetylacetonate and Tin(IV) bis(acetylacetonate)dichioride in oleyamine solvent under the condition of the different reaction time from 12 h to 48 h for the first time. The morphology, phase composition and particle size of the ITO powder were characterized by TEM and XRD. Two significant properties required for ITO samples to become noncarbon support for Pt in PEMFCs including specific surface area and electrical conductivity were studied. 展开更多
关键词 ITO indium doped tin oxide SOLVOTHERMAL CONDUCTIVITY NANOPARTICLES
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Risk of North Pole Route on Suez Canal Revenue
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作者 Capt. Ahmed Dawood Capt. Ahmed Sharabia 《Journal of Shipping and Ocean Engineering》 2017年第2期65-73,共9页
The inauguration of the North Pole route as an alternate route for transporting cargoes between the Far East and Europe appears to be extremely acceptable by shipping companies owing to the huge saving in fuel consump... The inauguration of the North Pole route as an alternate route for transporting cargoes between the Far East and Europe appears to be extremely acceptable by shipping companies owing to the huge saving in fuel consumption, bunker cost, operating cost, emissions and journey time. This route conversion will not only have an impact on the maritime business activity in the Suez Canal, but also the Egyptian economy in several aspects when the number of vessels passing through the Suez Canal and the Indian Ocean decreases. The aim of this study is to analyze the impact of the opening of the Northern Sea route on maritime sector of the Egyptian economy. The scope of this study is concentrating on the Suez Canal shipping activity by using the statistics that have been received from Suez Canal Authority through a set of direct and indirect interview sessions with authority's experts. 展开更多
关键词 Suez POLE CARGO ARCTIC revenue.
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Simulation of Biogas Production from Solid Organic Wastes
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作者 Ignacio Contreras-Andrade Jonathan Parra-Santiago Carlos Alberto Guerrero-Fajardo 《Journal of Chemistry and Chemical Engineering》 2015年第2期107-112,共6页
The design and building of new alternative fuel plants is an increasing necessity to replace old technology and non-renewable fossil fuels. To optimize the performance of these plants and to obtain an economically fea... The design and building of new alternative fuel plants is an increasing necessity to replace old technology and non-renewable fossil fuels. To optimize the performance of these plants and to obtain an economically feasible production of these types of fuels, it is necessary to have a total control of each variable involved in the process of production and how these factors affect the yield of fuel production. In this paper it is proposed a model of a digester to generate gas using a Vensim software designed to generate simulations in dynamic state. This simulation was developed using differential equations to model the behavior at each stage of the process and auxiliary conditions to complement the mathematical description of the model. The main factors in the biogas production are the retention time and the methanogen mortality ratio. For retention time lower than 10 h the process loses effectiveness due to bacterial growth is not completed efficiently, but a high retention time involves a bigger reactor and the yield of production decreases considerably for retention time higher than 40 h. The best yields were obtained for a mortality ratio in methanogen and acidogenic bacteria lower than 0.2 and a retention time of 30 h with a final production of 3.33 L by each kilogram of biomass. 展开更多
关键词 Bio-digester bio-digestion gas synthesis renewable energy.
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Applicability of Waterside Corrosion Models in Range of IFPE Database
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作者 Jun Wang Tong Liu Yuemin Zhou 《Journal of Energy and Power Engineering》 2014年第2期318-325,共8页
Fuel rod cladding waterside corrosion is one of the phenomena that limit the life time of nuclear fuel. Corrosion performance depends on the cladding material properties as well as operating conditions during the irra... Fuel rod cladding waterside corrosion is one of the phenomena that limit the life time of nuclear fuel. Corrosion performance depends on the cladding material properties as well as operating conditions during the irradiation of the fuel. As a function of temperature, power history, water chemistry, time, etc., waterside corrosion is of great concern in fuel performance evaluation, especially for high burnup fuels. This paper is dedicated to the study of the waterside corrosion phenomenon using the IFPE database by COPERNIC, which is developed for the analysis of fuel rod behaviors in normal operation and transient conditions. Different models, MATPRO, FRAMATOME and EPRI models, for example, are adopted in the simulations. The results derived from the models are compared and the unconformities are analyzed. Based on the comparative analysis, reasonable models are chosen to simulate certain irradiated fuel rods. Our analyses indicate that potential affecting factors which are not considered in COPERNIC code, such as water chemistry and alloy composition, should be responsible for discrepancies of certain rod predictions. 展开更多
关键词 Waterside corrosion model comparison influencing factors IFPE database.
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Efficient reversible CO/CO_(2) conversion in solid oxide cells with a phase-transformed fuel electrode 被引量:7
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作者 Yihang Li Manish Singh +5 位作者 Zechao Zhuang Yifu Jing Fengjiao Li Kristina Maliutina Chuanxin He Liangdong Fan 《Science China Materials》 SCIE EI CAS CSCD 2021年第5期1114-1126,共13页
The reversible solid oxide cell(RSOC)is an attractive technology to mutually convert power and chemicals at elevated temperatures.However,its development has been hindered mainly due to the absence of a highly active ... The reversible solid oxide cell(RSOC)is an attractive technology to mutually convert power and chemicals at elevated temperatures.However,its development has been hindered mainly due to the absence of a highly active and durable fuel electrode.Here,we report a phase-transformed CoFe-Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(CoFe-SFM)fuel electrode consisting of CoFe nanoparticles and Ruddlesden-Popper-layered Sr_(3)Fe_(1.25)Mo_(0.75)O_(7)-δ(SFM)from a Sr_(2)Fe_(7/6)Mo_(0.5)Co_(1/3)O_(6)-δ(SFMCo)perovskite oxide after annealing in hydrogen and apply it to reversible CO/CO_(2)conversion in RSOC.The CoFeSFM fuel electrode shows improved catalytic activity by accelerating oxygen diffusion and surface kinetics towards the CO/CO_(2)conversion as demonstrated by the distribution of relaxation time(DRT)study and equivalent circuit model fitting analysis.Furthermore,an electrolyte-supported single cell is evaluated in the 2:1 CO-CO_(2)atmosphere at 800℃,which shows a peak power density of 259 mW cm^(-2)for CO oxidation and a current density of-0.453 A cm^(-2)at 1.3 V for CO_(2)reduction,which correspond to 3.079 and3.155 m L min-1cm^(-2)for the CO and CO_(2)conversion rates,respectively.More importantly,the reversible conversion is successfully demonstrated over 20 cyclic electrolysis and fuel cell switching test modes at 1.3 and 0.6 V.This work provides a useful guideline for designing a fuel electrode through a surface/interface exsolution process for RSOC towards efficient CO-CO_(2)reversible conversion. 展开更多
关键词 reversible solid oxide cells CO-CO_(2)conversion perovskite oxide phase transformation cyclic test
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