OPTIMAL WINDING DESIGN OF A PERMANENT MAGNET MOTOR FOR SELF-CONTROLLED INVERTER OPERATION

ABSTRACT

This paper describes a novel design of the three-phase synchronous motor which is tailored to match the operational characteristics of the self-controlled inverter. The design is based on a square waveform distribution of the rotor radial B-fields and square waveform distributions of the winding densities of the stator phases around the periphery of the airgap. The motoring torque has minimal time harmonics. The design achieves a maximum power density for the frame size of the motor. It is ideally suited for permanent magnet synchronous motors.     

棕榈油部分替代猪板油及其相容性研究

选用棕榈液油(OL)与棕榈硬脂(ST)部分替代猪板油,对其理化性质及相容性进行分析,并使用欧式距离法确定复配棕榈油替代猪板油配方。结果表明:棕榈油替代猪板油在理化性质、健康方面具有明显的优势;棕榈油与猪板油之间的相容性与温度和质量分数有密切的关系,整体来看,二元体系低温下易出现偏晶现象,高温下易出现共晶现象,温度越低,相容性越差,温度在35~40℃之间时,相容性较好;通过相似度比较得出,质量分数为30%的ST和70%的OL复配时,可以作为部分替代猪板油的配方。     

STIFFNESS AND DAMPING MATRICES IN FREE-BODY TRANSLATIONAL ELECTROMECHANICS

ABSTRACT

Mathematical consistency requires three-dimensional translational electromechanics to be characterized by stiffness and damping matrices (order 3×3). This paper offers a physical interpretation to these matrices. It is shown that their eigenvalues yield the stiffness and damping constants and their eigenvectors yield information as to the orientations of their axes.

It is proved that the stiffness matrix is symmetric as a consequence of conservativeness     

LITHIUM-ION SIEVE PROPERTY OF λ;-TYPE MANGANESE OXIDE

The adsorptive properties of A-Mn0₂for mono and divalent metal ions were investigated by pH titration and by measurements of the distribution coefficients(Kd's) of the metal ions. The pH titration curve showed an apparently monobasic acid type for a H⁺-Li⁺exchange. Those for H⁺-K⁺and H⁺-Cs⁺exchanges were nearly the same as that for blank titration. The lithium ion uptake increased with increasing solution pH and reached 5 meq/g at pH 11. X-ray diffraction analyses showed that the adsorption of lithium ions caused an increase in the lattice constant of a cubic unit cell. The potassium and cesium ion uptakes were nearly zero over a pH range between 4 and 11. A-Mn0₂showed a remarkably high Kd value for lithium ions, compared to a cation exchange resin. The selectivity sequences were Na⁺< K⁺< Rb⁺< Cs⁺<< Li⁺for alkali metal ions, Mg²⁺< Ca²⁺< Sr²⁺< Ba²⁺for alkaline earth metal ions, and Ni²⁺< Zn²⁺< Co²⁺< Cu²⁺for transition metal ions.     

以红棕油为基料油的营养调和油研制

依据2013年中国营养学会推荐的脂肪酸摄入量的要求,以脂肪酸平衡和营养物质的含量为评价指标,使用红棕油为调和油的关键基料油,添加富含生理活性物质较多的稻米油、橄榄油、胡麻油,制备出4种不同比例的红棕调和油,通过气相色谱仪和高效液相色谱仪检测调和油中的脂肪酸组成和营养成分,结果表明:4种调和油中脂肪酸比例均符合中国营养学会推荐的脂肪酸摄入量的要求,且调和油中还含有丰富的β-胡萝卜素、γ-谷维素、角鲨烯、生育酚与生育三烯酚和植物甾醇。因此,4种红棕调和油是营养的调和油,为其它营养调和油的研制提供了参考。     

The politics of public space planning in Singapore

This paper considers the role of, and hence the social and political significance that has been accorded to, the design and provision of public spaces in the urban planning process. This approach gives useful insights into understanding the role these spaces have played in the colonial and post‐colonial city of Singapore. This discussion argues that public spaces in both the colonial and the post‐colonial city are essentially constructions by the ruling élite and its planning regime and are thus politically charged. Popular involvement has been singularly lacking in the planning and development of public spaces in post‐colonial Singapore. Instead, the general public has been marginalized in the creation of these spaces by the colonial and post‐colonial state. The completeness of this exclusion is shown through the demise of most of the vital and liveliest, albeit previously appropriated, public spaces of the colonial city. Public housing and the re‐invention of public spaces provided by a new social and political order followed the end of British colonial rule. In the following discussion, the role and significance of public spaces through the colonial period and then in the post‐colonial developmental state are examined. It is shown that public space provision by government authorities has served initially more as an imposition of colonial ideals and social segregation, and latterly as a reification of the prevailing political ideology, than in meeting real public needs for such spaces. A major focus of this article is the use of public space as a political tool of control by the state over its denizens in the Foucauldian sense, and how this could be construed even through different systems of governance and political agendas in Singapore.