Purchase contract management with demand forecast updates

We study a two-stage purchase contract with a demand forecast update. The purchase contract provides the buyer an opportunity to adjust an initial commitment based on an updated demand forecast obtained at a later stage. An adjustment, if any, incurs a fixed as well as a variable cost. Using a dynamic programming formulation, we obtain optimal solutions for a class of demand distributions. We also discuss how these results can be applied to gain managerial insights that help in making decisions regarding where to allocate efforts in improving the forecast quality and whether or not to sign a contract.     

宁夏海原县南、西华山地区与中酸性侵人岩有关的Au Cu成矿系列

论述了宁夏海原县南、西华山地区中酸性侵入岩及其派生脉岩的特征岩浆岩的演化、金铜矿化的类型,并以岩浆演化为纲,建立了本区与中酸性侵入岩有关的、成矿系列。     

平面全息光栅制作过程中精确判断线槽的新方法

本文提出了在平面全息光栅制作过程中精确判断线槽的新方法,指出了采用球面波获得直线形线槽的途径,对平面全息光栅光栅常数的检验精度给予了分析。结果表明,该方法能够大大地提高平面全息光栅槽距及直线性的制作精度     

蜂窝纸板力学性能的试验研究

在试验的基础上,研究蜂窝纸板的力学性能,得到了蜂窝纸板的压缩曲线及卸载曲线、二次加载曲线。结果表明,二次加载时,蜂窝纸板的应力—应变曲线将首先上升到预压时的卸载点。二次加载曲线表明,蜂窝纸板在用作缓冲材料时,若进行预压,使之进入屈服阶段,则缓冲效果会更好。     

加速溶剂萃取-气相色谱法快速测定食品中反式脂肪酸

应用加速溶剂萃取（ASE）技术对食品中的油脂进行富集,经甲酯化反应后,通过HP-88毛细管色谱柱分离测定食品中反式脂肪酸含量。结果：在提取温度125℃,提取压力1500psi,以正己烷／二氯甲影甲醇（3：2：1,V／V／V）可对食品中反式脂肪酸进行有效提取,以C16：1-t9为例,该方法加标回收率在96．1％～99．3％,相对标准偏差为0．5％～2．3％,最低检测限为2．0μg/mL,顺、反式脂肪酸分离良好。该方法简单、快速、所耗溶剂少、效率高,适用于食品中脂肪酸的测定。     

毛细管气相色谱法测定培哚普利中有机溶剂残留量

建立了毛细管气相色谱内标法测定培哚普利中甲醇、乙酸乙酯、甲苯等有机溶剂残留量的方法。以苯为内标,样品用二甲基亚砜溶解直接进样测定,色谱柱为CP—SIL8CB毛细管柱（30m×0．25mm×1．0μm）。有机溶剂残留添加回收率在98．1—100．8％之间,有机溶剂残留的最小检出限在0．1～0．25μg／mL之间。该方法具有快速、准确、操作简便等特点,能满足培哚普利中甲醇等有机溶剂残留量的定量检测。     

Inventory control and pricing with alternative lead times

Based on the recognition that customers are both price and lead-time sensitive, sellers nowadays often pursue a delivery-time based market segmentation strategy. In this paper, we consider an inventory model where the seller provides two delivery options with possible delivery upgrade. The inventory is replenished in cycles and within each cycle, the seller employs commitment control to allocate its on-hand inventory between two classes of customers. We develop the optimal inventory allocation and replenishment policies, and demonstrate that the optimal control can be characterized by a switching curve. In the further analysis, we subsume dynamic pricing as an effective means to balance the two demand streams. Finally, we investigate similarities and differences between the pricing and delivery upgrade strategies.     

改进嵌入原子法计算合金体系的研究进展

改进嵌入原子法是基于原子层次的半经验理论方法,广泛应用于纯金属元素和二元、三元合金体系的计算模拟.针对不同的物理性质对近几年改进嵌入原子法在合金计算方面的研究成果进行了归纳分析.改进嵌入原子法较为精确地反映了合金的各项物理性质,将会得到更为广泛的应用.     

修造船期间杂散电流腐蚀的电力线分布研究

对修造船期间的杂散电流进行了勘查和测试,分析了杂散电流腐蚀的原因,绘制了杂散电流腐蚀时的电力线分布图,并探讨了电力线的分布规律．     

钡钨阴极表面的光电子谱研究

用XPS,APES和ARPES分析技术综合探测了钡钨阴极(包括铝酸盐、钨酸盐和钪酸盐阴极)的表面化学,获得了一些新的结果。实验表明:阴极表面光电子谱峰的形貌特征与阴极的激活状态呈对应的关系;激活后钡钨阴极表面的钨是单一金属态,钡呈现氧化态。