大型泵站机组飞逸转速的确定及电机强度设计

以杭州三堡排涝工程为例,针对水泵机组设备重要参数飞逸转速确定进行分析,用最终确定的参数对电动机制造设计计算复核,经过建模计算,分析认为对电动机机械强度安全是有裕度的,能确保设备安全.同时也从工程角度说明选定合理的技术参数是经济可靠的工程建设原则,对其他同类工程建设有借鉴意义.     

基于制造业多粒度模型下的流程优化组合

在多粒度模型下对4个服务质量因子进行了性能的评估,并且根据实际云制造的生产情况引入了距离因子,并跟原有的性能描述进行对比。结果表明:引入了距离因子以后,表现出的服务组合性能和原始服务组合性能有所不同,这种表现更接近实际情况。     

Tri-level programming model for combined urban traffic signal control and traffic flow guidance

In order to balance the temporal-spatial distribution of urban traffic flow, a model is established for combined urban traffic signal control and traffic flow guidance. With consideration of the wide use of fixed signal control at intersections, traffic assignment under traffic flow guidance, and dynamic characteristics of urban traffic management, a tri-level programming model is presented. To reflect the impact of intersection delay on traffic assignment, the lower level model is set as a modified user equilibrium model. The middle level model, which contains several definitional constraints for different phase modes, is built for the traffic signal control optimization. To solve the problem of tide lane management, the upper level model is built up based on nonlinear 0-1 integer programming. A heuristic iterative optimization algorithm(HIOA) is set up to solve the tri-level programming model. The lower level model is solved by method of successive averages(MSA), the middle level model is solved by non-dominated sorting genetic algorithm II(NSGA II), and the upper level model is solved by genetic algorithm(GA). A case study is raised to show the efficiency and applicability of the proposed modelling and computing method.     

中西方宗教雕塑不同视觉风格影响及溯源

雕塑是人类最早的艺术活动之一,宗教雕塑是雕塑艺术的重要组成部分。西方宗教雕塑注重写实,中国宗教雕塑注重写意;西方宗教雕塑真实生动、细致入微,中国宗教雕塑整体概括、气势恢宏。中西方宗教雕塑不同视觉风格的形成有着复杂的形而上和形而下的原因。就内因而言,是宇宙观、审美心理、情感表达方式等方面的差异,从外因而言,是哲学和自然科学、安放环境、外来文化、材料及处理等不同。追溯中西方宗教雕塑视觉风格的成因将有助于中西方的人文交流与文明互鉴。     

海上地震拖缆拉力计算与应用

拖缆拉力是海上地震作业中一个重要指标,这直接关系到水下设备的使用寿命和安全.在冰区进行海洋地震勘探,对作业人员和设备都是极大的考验.出于设备安全考虑,应使用海锚代替尾标来应对拖缆等浮和摇摆问题.但在这方面国内外做的极少,并无现成经验可供参考,特别是对尾标和海锚的拉力没有一个准确的概念,不知道效果如何.这样工作人员只能通过测试和计算来确定海锚的使用方法和数量,保证顺利、高效、安全的作业.     

Simple Preparation of Crystal Co3（BTC）2·12H2O and Its Catalytic Activity in CO Oxidation Reaction

Crystalline metal-organic framework cobalt(Ⅱ) benzenetricarboxylate Co3(BTC)2?12H2O(MOF-Co) has been prepared using solvothermal method. The reaction of cobalt(Ⅱ) nitrate and 1,3,5-benzenetricarboxylic(BTC) acid in a mixed solution of N,N-dimethylformamide(DMF)/C2H5OH/H2O(1:1:1, ν/ν) at low temperature for short reaction times produced this crystalline compound. Compared with traditional hydrothermal method, a mixed solution method for the synthesis of crystalline metal complex was found to be highly efficient. After water molecules were removed from this metal complex, its exposed nodes served as active sites. When this MOF-Co was employed in the oxidation of CO, it showed good catalytic properties causing 100% conversion of CO to CO2 at low temperature of 160 ℃.     

Microstructure and properties of cement foams prepared by magnesium oxychloride cement

Microstructural features including pore size distribution, cell walls and phase compositions of magnesium oxychloride cement foams (MOCF) with various MgO powders and water mixture ratios were studied. Their influences on compressive strength, water absorption and resistance of MOCF were also discussed in detail. The experimental results indicated that moderate and slight excess MgO powders (MgO/MgCl₂ molar ratios from 5.1 to 7) were beneficial to the formation of excellent microstructure of MOCF, but increasing water contents (H₂O/MgO mass ratios from 0.9 to 1.29) might result in opposite conclusions. The microstructure of MOCF produced with moderate and slight excess MgO powders could enhance the compressive strength, while serious excess MgO powders addition (MgO/MgCl₂ molar ratios = 9) would destroy the cell wall structures, and therefore decrease the strength of the system. Although MOCF produced with excess MgO powders could decrease the water absorption, its softening coefficient was lower than that of the material produced with moderate MgO powders. This might be due to the instability of phase 5, the volume expansion and cracking of cell walls as immersed the sample into water.     

窄粒级煤泥浮选经典动力学模型的改进

通过煤泥窄粒级浮选速率实验,以煤泥浮选一级动力学为基础,对煤泥浮选动力学的关键参数进行研究,包括最大可燃体回收率ε∞的计算、浮选级数n的确定、浮选速率常数K的变化.结果表明:浮选动力学模型中ε∞的经验解比模型解更符合实际;窄粒级煤泥的浮选动力学级数最符合一级动力学;窄粒级煤泥的浮选速率常数K是时间的函数,可用幂函数或经验公式表达,先求出ε∞的经验解,再求解K(t)函数,所得模型非常符合煤泥浮选特征的浮选动力学模型.     

Unsupervised SAR image segmentation using TMF and belief propagation

To solve the problem that the traditional statistical inference approach for the triplet Markov fields (TMF) model cannot balance segmentation accuracy and computational efficiency, an efficient statistical inference approach for the TMF model using belief propagation is proposed, and then applied to unsupervised synthetic aperture radar (SAR) image segmentation. The algorithm combines the TMF model and the statistical property of the SAR image, and translates the segmentation problem into maximization of the posterior marginal (MPM) estimation. For the two label fields in TMF, the belief propagation algorithm is generalized to the bivariate case to estimate the joint posterior marginal probability of the two label fields through message passing. The two label fields can be simultaneously estimated according to the MPM criterion. Experiments on both simulated and real SAR images demonstrate that the proposed algorithm can efficiently suppress the influence of the speckle, and obtain accurate segmentation results with a reasonable computational cost.