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Search Results: 1 - 10 of 33885 matches for " 蒲鹏 "
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“法治国家”:一个深化依法治国思想的表述
英?
天府新论 , 1998,
Abstract:
石墨成孔法制备的两种铜基载氧体释氧以及循环反应特性
,, 张力
中国电机工程学报 , 2013,
Abstract: 通过石墨成孔浸渍法制备了Cu6Ti4和Cu6Si4这2种氧解耦化学链燃烧铜基载氧体,并利用热重分析仪、X衍射仪和扫描电镜对其进行了研究,主要考察了不同反应温度和不同氧气分压下的释氧特性,以及1?000?℃温度下的循环稳定特性等。热重实验结果表明:随着反应温度的增加,载氧体的转化速率,即载氧体中氧气的释放速率加快。Cu6Ti4载氧体在温度较低时的释氧性能要优于Cu6Si4载氧体,且Cu6Ti4载氧体在不同氧气分压下的开始释氧温度都要低于Cu6Si4载氧体。经过20次释氧/吸氧往复循环后,Cu6Si4载氧体仍然保持着很好的释氧吸氧能力,载氧量仅下降0.5%,而Cu6Ti4载氧体下降了1.5%。通过扫描电镜观察了两种载氧体循环反应前后的物相结构,结果发现Cu6Si4载氧体经过20次反应后,其表面结构仍有多孔结构,有利于氧气的析出和结合。
一类3阶非线性系统的非奇异终端滑模控制
Nonsingular terminal sliding mode control for a class of 3-order nonlinear systems

,蒋涛,
控制理论与应用 , 2017, DOI: 10.7641/CTA.2017.60693
Abstract: 针对传统非奇异终端滑模控制方法不适用于3阶系统的问题,提出一类具有不确定和外干扰的3阶非线性系统的新型非奇异终端滑模控制方法.该方案首先结合Backstepping控制中的动态面方法和传统二阶非奇异终端滑模控制构造非奇异3阶终端滑模面,首次提出采用高阶滑模微分器估计值代替控制器中的负指数项.采用非线性干扰观测器任意精度地估计不确定和干扰,设计控制器中的补偿项.采用终端吸引子函数做趋近律避免抖振的同时能保证有限时间趋近滑模面.基于有限时间稳定李雅普诺夫定理证明了被控状态将在有限时间内收敛到任意小的闭球内.所提出方案快于传统的递阶线性滑模控制和其他非奇异终端滑模控制.仿真中与其他滑模控制方案对比,总误差减小18% 以上,超调及收敛时间也显著下降.
Traditional nonsingular terminal sliding mode control cannot be used for 3-order systems. To solve this problem, a novel nonsingular terminal sliding mode control for a class of 3-order nonlinear systems with uncertainties and disturbances is proposed. Firstly, the dynamic surface of Backstepping control is combined with 2-order nonsingular terminal sliding mode control (TSMC) to construct the 3-order nonsingular terminal sliding modes. Then, the approximations of negative fractional exponential terms are obtained by higher-order sliding mode differentiator (HOSMD) to eliminate the singularity. Then, nonlinear disturbance observer (NDO) is used to approximate unknown uncertainties and disturbance. Terminal attractor is used as reaching law to avoid controller chattering. Based on finite time stability Lyapunov theorem, it is proved that the proposed scheme will force system states into an arbitrary small neighborhood including the origin in finite time. The proposed scheme has faster convergence speed than recursive linear sliding mode control (RLSMC) and other nonsingular TSMC (NSTSMC). In simulation, the total error of the proposed method decreased at least 18% compared with other sliding mode controllers. Overshoot and convergent time are also decreased significantly.
一种基于卡尔曼滤波算法的智能型自动扶梯安全性参数测试仪
An Escalator Security Performance Instruction Based on the Kalman Filter Algorithm
 [PDF]

陈杰, 郑徐豪, 吴德操, 唐跃林,, , 魏彪
Computer Science and Application (CSA) , 2014, DOI: 10.12677/CSA.2014.49030
Abstract:
针对自动扶梯或自动人行道自动扶梯安全性参数检测的快速、准确需要,采用增量式光电编码器为传感检测单元,以STM32处理器为最小系统,基于卡尔曼滤波算法,本文设计了一种智能型自动扶梯安全性参数测试仪,以此对自动扶梯制停距离、扶手带和梯级速度及其同步率和加速度等安全性能参数进行实时测量。测试结果表明,测试仪的自动扶梯速度估计和加速度估计相对误差未超出10%的行业规范性要求。
To detect escalator safety parameters fast and accurately, an intelligent automatic escalator safety parameter test instrument is designed. The instrument is using the incremental photoelectric encoder as the sensor and the STM32 processor as the minimum system in order to measure braking distance, handrails, cascade speed, the synchronization rate and acceleration parameters. The test results show that, the relative error between escalator speed estimation and acceleration estimation does not exceed the industry standard which is 10%.
壳聚糖席夫碱钯配合物催化碘代苯与苯乙烯交叉偶联反应的研究
,,王向宇
分子催化 , 2006,
Abstract: 水杨醛与壳聚糖反应制得壳聚糖席夫碱配体,此配体与钯盐反应得到壳聚糖席夫碱钯催化剂.研究了该催化剂对碘代苯(PhI)与苯乙烯偶联生成反式-二苯乙烯的催化性能.考察了不同反应因素(原料比、缚酸剂种类及其用量、反应温度、溶剂、催化剂用量、反应时间)对该反应的影响,由此确定了该催化反应的最佳反应条件.该催化剂经过滤分离、溶剂洗涤,循环使用6次仍有较高的催化活性,该催化剂对取代碘苯与苯乙烯的反应也有较高的催化活性.
要理性和谨慎处理生物能源与粮食安全问题
,王雅
农业现代化研究 , 2008,
Abstract: 在国际上,原油价格的不断上涨引起了生物能源的开发,但在我国特殊国情下,生物燃料的发展出现了与人争粮的问题,如果对生物燃料的发展不加以干预和监控,就有可能对粮食安全造成不良影响。应该根据国情,理性对待生物燃料和粮食安全问题,要在政府监管下,通过制定相应的政策和措施,大力发展非粮能源作物,开发非粮生物燃料作物技术,在不影响粮食安全的前提下,谨慎发展生物燃料。
板材类生物质燃烧及动力学特性热重研究
,雷强,
环境工程学报 , 2012,
Abstract: 采用非等温升温法研究了4种板材类生物质在空气气氛下的燃烧特性和动力学特性。通过对TG、DTG等曲线的分析,发现4种板材燃烧过程均可分成3个阶段,即水分蒸发阶段、挥发份析出(或燃烧)阶段和固定碳燃烧阶段。综合燃烧特性:松木集成材>纤维密度板>夹芯胶合板>刨花板。4种板材均具有良好的燃烧特性。4种生物质燃烧均存在1个吸热峰和2个放热峰,分别与挥发分析出峰、挥发分燃烧、固定碳燃烧对应。采用Fridman法和Fridman-Carroll法分别对4种板材的动力学参数进行了计算,2种方法得出的结果符合较好。分析得出:由于生物质燃烧与环境换热、挥发分析出吸热、固定碳燃烧放热等因素作用,4种生物质的表观活化能高温区均低于低温区。动力学计算结果表明:松木集成材平均表观活化能最低,燃烧反应能较容易进行。
尺寸效应对sio2纳米管化学屏蔽张量的影响
,徐灿,解淑玉
物理化学学报 , 2011,
Abstract:
非标称对流层误差对GBAS完好性的影响
Impact of non-nominal troposphere error on GBAS integrity

,王志
- , 2017, DOI: 10.13700/j.bh.1001-5965.2016.0665
Abstract: 摘要 地基增强系统(GBAS)中,非标称对流层误差引起的平均垂直保护级(VPL)增量为2.29 m,误差包络精度降低,系统完好性风险增大。针对上述问题,基于修正的Hopfield模型,综合考虑天气和卫星仰角实时变化情况,以及飞机与地面站的实时距离,提出一种实时计算非标称对流层误差的方法;鉴于该方法对甚高频频数据播发(VDB)传输带宽要求较高,提出拟合计算方法,将实时误差拟合为距离和卫星仰角的函数。仿真计算单点、进近区和终端区3种飞行场景下的VPL,分析非标称对流层误差对GBAS完好性的影响,结果表明:采用实时计算方法时,平均VPL增量为1.55 m,非标称对流层误差的包络精度提高32.52%;采用拟合计算方法时,平均VPL增量为1.27 m,包络精度提高44.54%,VDB传输数据减少,GBAS完好性风险降低。
Abstract:In current ground-based augmentation system (GBAS), the average vertical protection level(VPL) increase caused by non-nominal troposphere error is 2.29 m, the accuracy of bounding is reduced and the integrity risk is increased. Faced with the above problems, a real-time method was proposed based on the modified Hopfield model. With real-time method, the non-nominal troposphere error was calculated according to the real-time weather changes, satellite elevation angle and the distance between aircraft and ground station. Given the high requirement of the real-time method for very high frequency data broadcast(VDB) transmission bandwidth, a fitting method was proposed, in which error is a function of distance and elevation angle. Simulations compute the VPL under the flight scenarios of single point, approach area and terminal area with the aim of evaluating the impact of non-nominal troposphere error on GBAS integrity. The results show that, with the real-time bounding method, VPL is averagely increased by 1.55 m and the accuracy of bounding is increased by 32.52%; with fitting method, VPL is averagely increased by 1.27 m, the accuracy of bounding is increased by 44.54%, the VDB transmission data is less, and the GBAS integrity risk is decreased.
NaLa1-xEux(WO4)2的燃烧法制备及发光性能
Combustion Synthesis and Luminescence Properties of NaLa1-xEux(WO4)2 Phosphors
 [PDF]

钱先华, 张大凤, 杜明霞, 高岩岩, , 张秀兰, 马婧
Material Sciences (MS) , 2012, DOI: 10.12677/ms.2012.21003
Abstract: 采用燃烧法制备了系列NaLa1–xEux(WO4)2红色荧光粉,探索了煅烧温度及Eu3+掺杂量对样品结构与发光性能的影响。分别利用X射线粉末衍射仪(XRD)、紫外/可见/近红外分光光度计(UV-vis)以及荧光分光光度计(PL)对样品进行了表征。结果表明:得到的样品具有四方晶系的白钨矿结构;荧光粉在紫外–近紫外波段均有较强的吸收,在394 nm近紫外光激发下得到发射谱图的主要发射峰为Eu3+的5D0→7F1橙光和5D0→7F2红光特征跃迁发射,红光发射的强度是橙光发射的~6.2倍,有利于得到色纯度较高的荧光粉。
NaLa1–xEux(WO4)2 red phosphors were successfully synthesized by the combustion method. The influences of calcination temperature and Eu3+ doping amount on the structure and luminescence properties of as-synthesized sam-ples were explored. The phase composition and optical properties of as-synthesized samples were studied by X-ray powder diffraction and photoluminescence spectra. UV-vis spectra were used to measure the light absorption spectrum of the phosphors. The results show that the samples have the similar scheelite phase structure belonging to tetragonal system and have strong absorption in the region of UV and near-UV. The luminescence results show that the emission spectra under 394 nm excitation consist of the orange region 5D0?7F1 (594 nm) and the red region 5D0?7F2 (617 nm). The high ratio of the red emission to the orange emission is advantageous to obtain a phosphor with good CIE chroma-ticity coordinates.
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