坦克动力装置历史沿革及未来发展研究

首先介绍了坦克动力装置的技术特点及技术规格,随后详细描绘了其历史沿革,重点研究了柴油机及燃气轮机等动力装置的技术现状,最后对其发展进行了展望.未来,坦克装甲车辆仍会将柴油机及燃气轮机作为主要动力来源,考虑到目前石油资源的日渐稀缺,发展以燃料电池为动力来源的坦克装甲车辆是一个重要技术方向,而制取代用燃料同样有着较好前景,...     

基于稀薄燃烧的CNG发动机涡轮增压控制

为了降低汽车废气对大气的污染,更好地开发与使用污染较少、经济便宜的汽车代用燃料,提出了一种基于稀薄燃烧的压缩天然气(CNG)涡轮增压发动机控制方法;该方法采用中冷涡轮增压,提高了燃气发动机的输出扭矩与功率;又采用基于λ型氧传感器和转矩预估的稀薄燃烧控制策略,燃料消耗量明显降低;用这种控制方法改进中冷增压机型的4D125柴油机,抑制改造后增压发动机高转速时过大扭矩,匹配出CNG燃料发动机;实验证明,这种控制方法实现了涡轮增压燃气发动机的理想外特性,具有较高的可靠性和实用性。     

PLC在燃料乙醇控制系统的应用

主要介绍了燃料酒精脱水控制系统的自动控制研究。燃料酒精脱水整体控制系统采用PLC对脱水装置实施时间程序控制和上位机监控系统，其中对系统中纯度为95％酒精进口流量与温度实施神经元网络控制，对冷却器压力进行无模型自适应MFA控制。为保证系统稳定，同时对酒精蒸气温度和冷却器温度进行MFA控制及蒸发器、成品罐、淡酒罐液位控制系统。     

我国CNG汽车的发展现状及趋势

当前,雾霾天气给人们的生活带来了重大影响,形成雾霾天气的根本原因在于污染物排放,而主要污染源为机动车尾气等。研发新能源汽车是改善汽车尾气的最有效和最根本的途径。目前汽车代用新型燃料中使用较为广泛的主要是天然气。大力推广天然气汽车,以天然气代替汽油和柴油等作为汽车新燃料,是有效降低汽车尾气污染的重要方式。     

环保航空

一辆1．6L排量的汽车,百公里耗油大概8升左右,而一辆波音737飞机每百公里耗油430升左右,也就是说,飞机一小时要烧掉3吨左右的燃料。巨大的燃料消耗不仅增加了航空公司的运营成本,排放的二氧化碳更是破坏了自然环境。有鉴于此,波音公司几年前就开始试验使用绿色能源,并于近日完成燃料电池驱动飞机的载人飞行。此次电池使用氢作为燃料,同时这也是全球第一架氢动力飞机,它是由一架螺旋桨动力滑翔机改装而成,波音公司为此花了5年时间进行研究测试。     

解封最后的封印 聊一聊发动机的内部强化(下)

正在上期的改装学堂中,我们了解了一台车子在经过排气系统、进气系统、点火系统、ECU调校、传动系统等一系列的升级改装后,发动机的缸内强化成为解开汽车最后潜力封印的方式。其实无论何种改装方式,想要压榨出汽车尽可能多的动力,所追求的都是让发动机缸内的燃料与空气的爆燃得更加激烈、更加充分。就像人的心脏一般,越激烈的运动,就需要心脏越快速的跳动去维持。而这期学堂所涉及的,是从效率的提升所演变成的动力强化。车子既然选择了对发动机内部进行强化,就不会忽略这个效率——进气效率。     

浅谈车用汽油机供油技术的发展及其对燃油性能的要求

1电子控制汽油喷射系统的发展及应用现代汽车上普遍使用的发动机是以汽油、柴油、气体燃料、煤气及液化石油气等为燃料的往复活塞式内燃机。其中以汽油或柴油为燃料的发动机技术较为成熟且应用广泛,简称为汽油机和柴油机。相对于柴油机而言,汽油机因具有体积较小,噪声低,技术成熟等优点而普遍应用于各类轿车及中、小型客、货车。汽油机的燃料是汽油,由原油中提炼出的轻质成分组成。汽车的运行性能与汽油燃烧状况息息相关。液态的汽油是无法燃烧的,所以进入气缸之前汽油必须先雾化和蒸发,然后与空气按一定的比例充分混合后,经进气门进入气缸并被火花塞点燃,产生压力推动活塞下行使发动机曲轴     

基于MC9S12的电控燃料喷射系统研究

利用单片机MC9S12,在单缸柴油机基础上设计乙醇/柴油双燃料发动机电控燃料喷射系统.分析了系统组成及功能,设计系统硬件电路,利用单片机输入捕捉输出比较时序控制、燃料喷射脉宽脉谱和双线性插值查表算法实现对乙醇燃料喷射量的精确控制.仿真及试验测试表明,利用该系统可实现不同工况下乙醇燃料变脉宽喷射,有效地进行乙醇/柴油混合...     

国内外玉米深加工产业发展对比分析

针对国外玉米化工产业发展现状及趋势,对比中国玉米产业发展状况及产业布局,提出了中国玉米深加工业应重点发展的几个方向:继续发展具有国际竞争力的柠檬酸、赖氨酸等传统产品,扩大淀粉、糖在食品工业等中的应用,适度发展玉米燃料酒精,鼓励发展纤维素酒精.进一步扩大变性淀粉的应用范围和领域,发展环境友好型的合成材料,代替石油生产化工醇、有机酸等产品.     

基于PI控制的内燃动车组柴油机恒功率控制技术

柴油机在非恒功率输出时,不仅燃料效率低,而且可能会产生较大的机械应力,导致机械部件的磨损和破坏。为确保内燃动车组柴油机高效运行,基于内燃动车组柴油发电机组恒功率输出的运行模式,文章提出了一种比例-积分控制方法,实现了负载侧牵引系统功率稳定跟随柴油发电机组的输出功率目标值,通过负载侧恒功率运行保障发电机组的恒功率稳定输出,从而提高柴油机燃油经济性。经过仿真及试验测试验证,采用此控制方法,负载功率稳态波动在±2%以内,实现了内燃动车组柴油机恒功率运行及负载功率对目标值的实时跟随。     

Hopfield在计算机编程中的应用与研究

Hopfield网络,又称联想记忆网络。文中根据Hopfleld神经网络构造一个应用于计算机代码编程中的联想存储器。联想记忆是该存储器的重要功能,它具有信息记忆和信息联想的特点,能够从不完整的或模糊的信息联想出存储在记忆中的某个完整清晰的信息模式。根据这一原理,用H0pfield联想存储器知识和eclipse插件机制来搭建嵌入在eclipse开发工具中一个知识可拓展的动态帮助插件,实现根据残缺不全的java代码联想到完整的java代码的功能,并进一步阐述Hopfield神经网络在计算机代码编程中的应用前景和发展方向。     

试谈计算机软件中的插件技术

应用插件技术,可以很好地提高软件的重用性和扩展性,解决软件合作开发与集成问题具有很好的理论和实用价值。介绍了插件技术的原理,阐释了插件的实现方案,提出了插件技术在地震处理插件系统中的应用。     

基于氧电极的乙醇微生物传感器的在线检测系统

乙醇氧化菌消耗利用乙醇,并产生溶解氧的特性,结合 Clark 氧电极技术设计一种新的乙醇微生物传感器检测方法.该微生物为嗜有机甲基杆菌,是以乙醇作为唯一的碳源生长的菌株.采用利于微生物细胞生长的 PVA-海藻酸盐溶胶-凝胶包埋法,对筛选、分离得到的乙醇氧化细菌固定处理,通过 Clark 氧电极对催化乙醇产生的溶解氧进行...     

柱式萃取设备中多组分传质的非平衡级模型计算

本文以轴向扩散柱塞流模型为基础，建立一种描述多级分传质的模型计算方法，研究结果表明，采用非平衡级模型计算方法，可以比较准确地反映柱内各截面上的各组分浓度，文中还分析了Ｈ２－ＨＮＯ３，ＵＯ２（ＮＯ３）２－３０％ＴＢＰ（煤油）竞争萃取体系中ＨＮ３浓度的“非单调”现象。     

Separation based adsorption of ethanol–water mixture in azeotropic solution by single–walled carbon,boron-nitride and silicon-carbide nanotubes

The separation of the azeotropic ethanol-water mixture (95.57 wt% ethanol) over a wide range of pressures (100–100000 kPa) was studied on armchair SWCNTs, SWSiCNTs and SWBNNTs with different diameters at 351.30 K using GCMC simulations. The GCMC results demonstrated that ethanol and water molecules form a monolayer single-file, chain together in the center of (6,6) SWCNT, while a spiral ring of ethanol and water is formed in the center of (8,8), (10,10) and (12,12) SWCNTs. It was found that in SWCNTs, the adsorption of ethanol reduces the function of pressure, while water adsorption increases its function. Water selectivity rises as a function of pressure. Also, in SWBNNTs, the adsorption of water increases as a function of pressure, while ethanol adsorption is almost constant. However, in the case of SWSiCNTs, ethanol and water adsorptions are very similar to those of SWBNNTs, whereas the adsorptivities of SWSiCNTs are more than those of SWBNNTs. Our findings regarding adsorption and slope of adsorption indicate that higher pressures are favorable for separating water and ethanol by SWCNTs, while SWBNNTs and SWSiCNTs are demonstrate higher ethanol adsorptivities in lower pressures. Also, MD simulations have been performed to study the microscopic structure and diffusion of binary mixtures of water and ethanol within SWCNTs, SWSiCNTs and SWBNNTs. The MD simulations imply that the oxygen atoms are highly well-organized around themselves. Also, the MD results illustrate a similar tendency for oxygen of water (OW) and oxygen of ethanol (OE) to the wall of the nanotubes in all the pressures. In addition, from the MD results, self-diffusion of water and ethanol in all nanotubes were calculated and discussed.     

Theoretical investigation of the selective dehydration and dehydrogenation of ethanol catalyzed by small molecules

Catalytic dehydration and dehydrogenation reactions of ethanol have been investigated systematically using the ab initio quantum chemistry methods The catalysts include water, hydrogen peroxide, formic acid, phosphoric acid, hydrogen fluoride, ammonia, and ethanol itself. Moreover, a few clusters of water and ethanol were considered to simulate the catalytic mechanisms in supercritical water and supercritical ethanol. The barriers for both dehydration and dehydrogenation can be reduced significantly in the presence of the catalysts. It is revealed that the selectivity of the catalytic dehydration and dehydrogenation depends on the acidity and basicity of the catalysts and the sizes of the clusters. The acidic catalyst prefers dehydration while the basic catalysts tend to promote dehydrogenation more effectively. The calculated water-dimer catalysis mechanism supports the experimental results of the selective oxidation of ethanol in the supercritical water. It is suggested that the solvent- and catalyst-free self-oxidation of the supercritical ethanol could be an important mechanism for the selective dehydrogenation of ethanol on the theoretical point of view.     

基于蓝牙技术的即插即用传感器系统研究与实现

主要介绍如何使传统传感器具有自我表述能力以实现即插即用功能。即通过读取传感器上嵌入的一块存储器上存储的TEDS,得知该传感器的所有重要信息。有效地克服了传统传感器的复杂搭建连线过程。此外,引入了蓝牙无线技术,对异地无线测量系统和即插即用测量设备的研究有一定的应用和参考价值。     

基于IMD的即插即用智能网关的设计和实现

随着上网宽带的普及，移动式的上网或办公的方式越来越广泛。然而当一个电脑从一个网络环境移动到另一个网络环境的时候，往往因为两地网络参数设置不同而不能正常上网。文中主要对基于Windows中IMD下实现一种即插即用智能型网关，使任意IP及网络参数的客户机接入到此网关中都能正确连接到局域网之外的任何节点。并且在网关上实现了一定的负载均衡机制。     

Polyelectrolyte conformational transition in aqueous solvent mixture influenced by hydrophobic interactions and hydrogen bonding effects: PAA–water–ethanol

Molecular dynamics simulations of poly(acrylic acid) PAA chain in water–ethanol mixture were performed for un-ionized and ionized cases at different degree-of-ionization 0%, 80% and 100% of PAA chain by Na⁺ counter-ions and co-solvent (ethanol) concentration in the range 0–90 vol% ethanol. Aspects of structure and dynamics were investigated via atom pair correlation functions, number and relaxation of hydrogen bonds, nearest-neighbor coordination numbers, and dihedral angle distribution function for back-bone and side-groups of the chain. With increase in ethanol concentration, chain swelling is observed for un-ionized chain (f = 0) and on the contrary chain shrinkage is observed for partially and fully ionized cases (i.e., f = 0.8 and 1). For un-ionized PAA, with increase in ethanol fraction ϕ_eth the number of PAA–ethanol hydrogen bonds increases while PAA–water decreases. Increase in ϕ_eth leads to PAA chain expansion for un-ionized case and chain shrinkage for ionized case, in agreement with experimental observations on this system. For ionized-PAA case, chain shrinkage is found to be influenced by intermolecular hydrogen bonding with water as well as ethanol. The localization of ethanol molecules near the un-ionized PAA backbone at higher levels of ethanol is facilitated by a displacement of water molecules indicating presence of specific ethanol hydration shell, as confirmed by results of the RDF curves and coordination number calculations. This behavior, controlled by hydrogen bonding provides a significant contribution to such a conformational transition behavior of the polyelectrolyte chain. The interactions between counter-ions and charges on the PAA chain also influence chain collapse. The underlying origins of polyelectrolyte chain collapse in water–alcohol mixtures are brought out for the first time via explicit MD simulations by this study.