Knowledge Mining of Low Specific Speed Centrifugal Pump Impeller Based on Proper Orthogonal Decomposition Method

To clarify the complex relation between the pump blade shape and its corresponding hydraulic performance, the knowledge mining method of centrifugal pump impeller based on proper orthogonal decomposition(POD) was proposed. The pump blade shape was parameterized by cubic Bezier curve. The Latin hypercube design method was employed to supply the necessary samples for producing the perturbations of blade wrap angle, and blade angle at inlet and outlet. The hydraulic efficiency and head were optimized by NSGA-II and RBF hybrid algorithm. The Pareto-optimal solutions were obtained. In order to further illustrate the relationship between the centrifugal pump blade shape and its hydraulic performance, the POD method was used to discover the effects of optimized blade shape to the flow solutions. For the optimization of centrifugal pump MH48-12.5, blade shape and relative velocity field in impeller from Pareto-optimal solutions were analyzed. The results demonstrate that larger blade angle and smaller wrap angle increase the average kinetic energy in impeller, resulting in higher pump head design. Smaller blade angle and larger wrap angle decrease the velocity gradient from the pressure side to suction side, resulting in smaller hydraulic loss and higher efficiency design.     

Polyoxometalate-based silica-supported ionic liquids for heterogeneous oxidative desulfurization in fuels

With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N_2 adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.     

基于标准水资源指数(SWRI)的流域水文干旱评估——以海河北系为例

构建了一个新的水文干旱评估指标——标准水资源指数(SWRI),结合分布式水循环模型、Copula函数及统计检验等方法,形成了一套完整的水文干旱识别、评估及特征分析的基本框架。以海河北系为例,定量识别了1956—2009年间的水文干旱事件,并对其干旱特征及变化规律进行了剖析。结果表明:海河北系近54年发生的34次水文干旱主要集中在短历时、低强度、小面积区间内,空间上主要分布在张家口、大同及北京等地区;干旱指标的联动关系上,干旱历时、强度与面积指标间呈显著的线性或指数相关关系,90%的水文干旱历时低于40个月、干旱面积占比不超过43%,干旱强度低于9.0;在给定的干旱特征指标值(如干旱面积)条件下,另一干旱指标值越大(如强度越大)干旱发生概率越小,且存在明显的特征区间;单变量水文干旱重现期介于联合重现期和同现重现期之间。     

中东原油馏分油加氢生产润滑油基础油

分析了中东原油馏分油的基本性质，综述了加氢裂化、加氢处理、加氢脱蜡、加氢精制及组合工艺的工业应用情况，探讨了由中东原油馏分油生产润滑油基础油应注意的问题，提出了适合炼油厂生产润滑油的建议。     

海底管道超声检测数据采集模块的设计

应用超声检测技术于海底管道探伤,具有快速、可靠、经济等优点;由于超声中心频率比较高,探头数目也较多,对超声数据采集系统提出了比较高的要求,正是针对这一问题,提出了一种基于LFECP33 FPGA DSP平台的数据采集方案,其中LFECP33是内含8个sysDSP的高性能FPGA,这套系统不仅具有采样频率高和多个通道实时处理高速大容量数据的能力,同时由于整套器件的功耗比较低,非常适用于管道检测中高压高温的环境特点,对超声技术应用于海底管道检测提供了很好的数据采集方案.     

2008奥运会羽毛球馆弦支穹顶结构模型动力特性试验及理论分析

对2008奥运会羽毛球馆弦支穹顶结构1∶10模型进行了动力特性的试验研究与理论分析。计算得出了模型不同施工阶段的频率值及振型;采用环境激励和正弦激励两种方法对模型的不同施工阶段进行了动力特性测定试验;阐述了试验的原理、过程及结果。研究表明:结构频率密集、周期较长、以竖直方向振动为主,振型大部分为正对称或反对称形态;结构阻尼比在0.02~0.03范围之内;理论计算结果与试验结果吻合较好。本文所得结论对2008奥运会羽毛球馆的设计、施工及今后相同结构设计具有参考意义。     

导弹仪器支架有限元分析

根据某导弹仪器支架的结构设计方案 ,利用大型有限元结构分析软件 ANSYS,采用梁、板壳和质量单元描述结构主体 ,用局部刚化模拟仪器支架转角和加强处 ,并对其上的仪器设备和电缆的模拟作了有益的尝试。通过细致的网格划分 ,建立了较为合理的结构有限元动力学计算模型 ,对其进行了结构强度和振动模态分析。计算结果预示和验证了仪器支架的结构性能 ,进而为进行结构振动控制设计提供了理论参考依据。     

电池模组垂直方向温度场仿真与实验分析

热管理系统在维持电池组内部热量均衡、使电池安全可靠、延长电池使用寿命方面发挥重要作用.利用Floefd软件对电池标准模组进行高度方向温度场热仿真分析,并开展验证实验.在电池组放电过程中测量模组底部、上表面、冷却板导热垫、侧板等高度方向各点温度,将仿真与实验数据进行对比分析.结果表明,典型工况时,电池模组上表面温度达到4...     

论我国北煤南运建设CWF加工业和CWF管道的可行性

据我国专家预测,我国在2030年之前,煤炭仍将是主要能源,北煤南运和节煤减排仍是长期的任务。分析了第二代水煤浆燃料(CWF)的优点:流变性稳定,储存期长(两年);加工过程并不复杂;可管输,埋于地下安全不冻,不受恶劣气候影响,无爆炸危险,可沿铁路铺设,不占农田。CWF发电NOx排放量比煤粉发电低20%～30%,又无堆煤场及煤粉加工粉尘危害。建议十二五规划中引进该项技术,在山西、陕西、内蒙古自治区西部交界地区建设CWF生产基地、集输管网并沿北煤南运三大铁路运煤通道敷设3条529mm实验CWF管道。采用开式流程和滚动开发技术,边建设边投产运行,尽快产生经济效益,立竿见影缓解北煤南运紧张度,以保证运输安全。     

Spectral and Laser Properties of Yb:LuAG Transparent Ceramics Fabricated by Tape Casting Method

Yb³⁺‐doped LuAG laser ceramics with different Yb³⁺‐doping concentrations were successfully fabricated by nonaqueous tape casting method and vacuum sintering technology. XRD patterns and SEM morphologies of the ceramics were presented. The optical in‐line transmittance of the Yb‐doped LuAG ceramics was about 83% at 1030 nm. The fluorescence lifetime of annealed and unannealed ceramic samples was compared. From the spectroscopic properties, it can be seen that the ceramics had a large emission cross section of 2.9 × 10^?20 cm² with a FWHM of about 7.2 nm at 1030 nm. Under 100% population inversion, the maximum gain coefficient was estimated to be 12.4 cm^?1 at 1030 nm. With a fiber‐coupled diode laser as pump source, CW laser at 1030 nm was demonstrated and the maximum output power of 338.9 mW was achieved with a slop efficiency of 19%. A tuning range from 1028 to 1036 nm was obtained.