喷雾沉积热分解法在SrTiO3和织构的Ag基底上制备YBa2Cu3O7-x涂层超导膜

本文研究了用喷雾沉积热分解法在(110)Ag单晶、{110}<011>Ag带、(100)SrTiO3三种不同的基底上制备YBa2Cu3O7-x涂层超导薄膜.通过对溶液成份,载气流量,沉积温度,退火时间等条件的系统研究,我们发现上述参数与薄膜的成份,表面形貌,织构以及超导性能有密切的关系.在Ag单晶基底上所获的YBCO薄膜具有很强的平面双轴织构,起始转变温度达到了90K,Jc值超过了104A/cm2(77K,0T);改进试验装置后,以织构Ag为基底,制备出了15cm长的YBCO超导带材,Jc值达到了104A/cm2(77K,0T).同时,我们发现温度梯度在热分解区间内对薄膜的形成起到了重要的作用.随后我们又在喷雾加热系统中附加一个金属加热圆筒,以改善加热区间的温度梯度,薄膜的性能得到了明显的提高.在(100)SrTiO3上的YBa2Cu3O7-x薄膜,(102)极图的FWHM值达到了0.70°,薄膜的起始超导转变温度为91K(ΔTc=1.5K),Jc值接近105A/cm2.     

Properties of Continous Models of Transfer Lines with Unreliable Machines and Finite Buffers

We consider a transfer line consisting of a series of machinesseparated by buffers of finite capacity. The processing of apart on a machine requires a fixed amount of time. In thesesystems, blocking and starvation, which occur as a consequenceof machine failures, are important phenomena. Except for transferlines without buffer storage, no exact models of such systemshave been reported in the literature, even in the case of two-machinelines. Two approximate models have been proposed: the discrete-timemodel and the continuous-flow model. Exact solutions of theemodels have been reported in the case of two-machine Lines,and approximations have been proposed for longer lines. Thepurpose of this paper is to provide properties of the continuous-flowmodel. The main result of the paper is to show that lower andupper bounds on the exact production rate of the transfer linecan be obtained using the continuous flow model. These boundsare obtained by making an appropriate choice of the buffer capacities     

Optimizing a model for multiproduct batch sizes with in-process inventories and multiple work centres

This paper deals with a model for multiproduct optimal batchsizes with in-process inventories and multiple work centresformulated by Bertrand (1985). Using well-known results fromLangrange duality, it is shown that the problem can be decomposedinto a series of one-variable optimization problems. Two algorithmsare suggested.     

MgB2／Fe带材Jc的各向异性及MgB2芯织构和成分不均一性的研究

本文研究了在不同磁场方向和温度下非原位Fe包套MgB2单芯带Jc的各向异性，通过对各种工艺条件下带材中MgB2芯的X-ray衍射图进行拟合分析和计算，比较了MgB2芯在Fe-MgB2界面和中心处的织构度和成份不均一性．研究发现带材Jc的各向异性受初始粉末颗粒尺寸的影响．由于受套管材料强度和形变加工工艺的影响，MgB2芯在Fe-MgB2界面处比在中心处有较强的织构．在MgB2-Fe的界面处，700℃淬火样品的X-ray衍射图中发现了由中间相Fe23B6生成的金属间化合物Fe2B另外还研究了MgB4和MgO等主要杂质相的形成原因．     

COMPARAISON ENTRE L''EMISSION D''OXYGENE ET L''EMISSION DE LUMINESCENCE A LA SUITE D''UNE SERIE D''ECLAIRS SATURANTS

Abstract— Luminescence of Chlorella cells has been measured after illumination by a series of short saturating flashes.
The intensity of luminescence is strongly dependent upon the number of flashes; luminescence is minimum after a single flash and maximum after a double flash illumination.
If l /_n is the intensity of luminescence measured 0.24 sec after the nth flash, the series l _n shows oscillations as a function of n. The series l _n is very similar to the series y _n, in which y is the amount of oxygen evolved by the nth flash, the term l _n corresponding to the term y _n+1. To interpret the oscillations of the series y _n, different models of system II photochemical centers have been proposed, one by ourselves and the other one by KOK et al. In these models the electron donor Z of photosystem 11 is supposed to have 2 or 4 levels of oxidation, the more oxidized state being the precursor of oxygen. These different oxidation states of the donor Z allow storage of the photic energy in the system. The correlation between the series y _n and l _n shows that at least one of the oxidized forms of the donor Z is a substrate for the luminescence reaction.