基于风险管理的动态供应链超网络均衡模型

基于风险管理的动态供应链超网络均衡模型的研究有助于供应链超网络节点厂商在动态环境下优化其风险管理,降低风险损失,提升供应链网络在风险管理下的竞争优势。本文以三层供应链超网络为研究对象,采用风险发生概率和损失函数表达供应链超网络中节点厂商中断风险的特征,构建了基于风险管理的动态供应链超网络均衡模型。模型中包括三种类型的节点,产品生产商、零售商和需求市场,生产商考虑风险损失的情况下,基于动态变化的风险、需求和成本追求个体期望效益最优化。接着,通过进化变分不等式来表达动态供应链超网络风险管理下的均衡解,并采用投影动态系统求解进化变分不等式,通过数值算例验证方法的可靠性和合理性,通过投影动态系统解释某一个厂商趋近均衡解的过程。通过单一厂商趋近均衡解的过程,阐述其他厂商相应的最优决策。     

VIP分析简化近红外光硬膜血肿检测的研究

多通道近红外光光密度差异检测硬膜血肿的方法具有快速、无创等优点，光源周围检测器数量与位置对降低硬膜血肿程度预测模型的病态性，提高血肿检测精度至关重要。提出了基于变量投影重要性(VIP)分析的检测器位置筛选方法。通过对距离光源位置2.0～5.0 cm范围内的30个检测器获得的光密度差异数据进行VIP分析，分析比较确定VIP阈值后从中筛选出4个检测器。以偏最小二乘法(PLS)建立基于4个检测位置获得的吸光度差预测血肿发生部位吸收系数的预测模型，检测器VIP优化后血肿位置吸收系数预测结果平均相对误差由4.08%降低到2.06%。可见利用VIP分析对检测器筛选后所建立预测模型仍可较好的对硬膜位置血肿程度进行判断。该研究为近红外光硬膜血肿检测中检测器位置的选择提供了新的思路和重要参考。     

离子液体处理含油污水实验研究

合成出了适合于含油污水处理的憎水性离子液体,研究了离子液体对含油污水的处理条件。当离子液体与含油污水体积比为1∶5,pH值为5,处理15min后,水中油的去除率为95.6%,COD_Cr的去除率为93.5%,表明应用离子液体可以有效地去除油田采出水中的有机物。同时考察了再生离子液体对除油效果的影响,其五次平行实验的除油率达95.4%,COD_Cr去除率为93.2%,表明离子液体可以回收利用。在此基础上,分析了离子液体对含油污水处理的作用机理。     

单金纳米棒的光散射分析化学:径向比与分析灵敏度的关系

单纳米颗粒作为信号感应单元在化学与生物传感应用中已引起广泛关注.本文通过暗场显微成像(iDFM)研究了不同径向比金纳米棒的光散射性质.将iDFM与扫描电子显微镜(SEM)结合表征种子生长法制备的金纳米棒,结果发现,因局域表面等离子体共振而展示出的红色散射光随单个金纳米棒的径向比增大逐渐红移,且金纳米棒对其周围介质折光率(RI)变化的敏感程度随径向比增大而增大.这一结果对设计高灵敏的生物纳米传感器、提高分析检测的灵敏度具有很好的指导意义.     

新型MEMS压电矢量水听器

对一种具有U形槽或双U形槽结构的MEMS压电式矢量水听器进行了仿真分析与优化,采用微机械加工技术研制出水听器芯片,并对芯片进行了封装与性能测试。提出了理论灵敏度和能量综合分析的方法,在考虑杂散电容的情况下,对敏感结构进行了更加精确的优化。从实验结果可以看出,所提出的优化方法比仅考虑理论灵敏度的传统优化方法具有更高的准确度。此外,具有双U形槽结构的矢量水听器的灵敏度比传统的单臂悬臂梁结构的灵敏度高约5.9 dB,并且具有良好的指向性。     

G-M制冷机驱动设计

为了使G-M制冷机在一定的氦气循环压力下提升制冷速度,通过对G-M制冷机(CTI-350C型)进行分析,运用变频和移相手段,设计并研制了低成本、便携的小型制冷机驱动,在输出频率为50 Hz时,制冷机空载条件下降温时间与M600压缩机驱动时降温时间相同;在60 Hz和70 Hz时,缩短了制冷机在空载条件下的降温时间20%以上,并具有过载保护功能。     

Estimation of biophysical properties of cell exposed to electric field

Excitable media,such as cells,can be polarized and magnetized in the presence of an external electromagnetic field.In fact,distinct geometric deformation can be induced by the external electromagnetic field,and also the capacitance of the membrane of cell can be changed to pump the field energy.Furthermore,the distribution of ion concentration inside and outside the cell can also be greatly adjusted.Based on the theory of bio-electromagnetism,the distribution of field energy and intracellular and extracellular ion concentrations in a single shell cell can be estimated in the case with or without external electric field.Also,the dependence of shape of cell on the applied electronic field is calculated.From the viewpoint of physics,the involvement of external electric field will change the gradient distribution of field energy blocked by the membrane.And the intracellular and extracellular ion concentration show a certain difference in generating timevarying membrane potential in the presence of electric field.When a constant electric field is applied to the cell,distinct geometric deformation is induced,and the cell triggers a transition from prolate to spherical and then to oblate ellipsoid shape.It is found that the critical frequency in the applied electric field for triggering the distinct transition from prolate to oblate ellipsoid shape obtains smaller value when larger dielectric constant of the cell membrane and intracellular medium,and smaller conductivity for the intracellular medium are used.Furthermore,the effect of cell deformation is estimated by analyzing the capacitance per unit area,the density of field energy,and the change of ion concentration on one side of cell membrane.The intensity of external applied electric field is further increased to detect the change of ion concentration.And the biophysical effect in the cell is discussed.So the deformation effect of cells in electric field should be considered when regulating and preventing harm to normal neural activities occurs in a nervous system.     

Coupling Effect of Ion Channel Clusters on Calcium Signalling

Based on a modified intracellular Ca^2＋ model involving diffusive coupling of two calcium ion channel dusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of dusters together with internal noise determine the calcium dynamics of single duster, and for either homogeneous or heterogeneous coupled dusters, the synchronization of dusters, which is important to calcium signalling, is enhanced by the coupling effect.     

［Mg(NH2)2］n(n=1—5)团簇的密度泛函理论研究

用密度泛函理论的杂化密度泛函B3LYP方法在6-31G^*基组水平上对［Mg(NH₂)₂］_n(n=1—5)团簇各种可能的构型进行几何结构优化，预测了各团簇的最稳定结构.对最稳定结构的振动特性、成键特性、电荷特性等进行了理论研究.结果表明：团簇易形成链状结构，Mg—N键长为0.190—0.234 nm，N—H键长为0.101—0.103 nm，H—N—H键角为100.2°—107.5°；团簇中M 关键词： 2)₂］_n(n=1—5)团簇')" href="#">［Mg(NH₂)₂］_n(n=1—5)团簇 密度泛函理论 结构与性质 储氢材料