分期付款期权在基于教育基金保险的期权中的应用

文献[1]提出了一种基于教育基金保险的欧式看涨期权,它赋予合约持有人在约定时间以约定价格购买连续支付固定年限的教育年金保险的权利,本文在[1]的基础上进一步提出基于教育基金保险的分期付款期权,该期权进一步改进了基于教育基金保险的欧式看涨期权,它赋予期权持有人分期支付期权费的权利,而不是一次性支付期权费,经过首期期权费的支付,期权持有人可以在继续支付期权费以持有期权和中断期权费的支付让期权作废之间选择,这样就可以使投资者在必要的时候取消期权,从而避免无效成本支出.该期权更加方便于低收入家庭和欲将资本用于其它高回报的投资的家庭进行教育投资.本文用后向递推和二叉树方法的方法给出期权定价公式,并确定分期支付的期权费的范围.     

视黄醇结合蛋白4与糖尿病视网膜病变的相关性研究

目的 探讨2 型糖尿病（T2DM）患者的视黄醇结合蛋白4（RBP4）水平与糖尿病视网膜病变（DR）的关系。方法 应 用酶联免疫吸附法测定31 例无DR 的糖尿病患者（NDR 组）、33例非增殖性DR 患者（NPDR 组）、34 例增殖性DR 患者（PDR组）和36例无糖尿病的健康体检者（对照组）的血清RBP4 水平,比较4组RBP4水平,并分析其与BMI、超敏C反应蛋白（hs-CRP）、TG 等的关系。结果 NDR 组、NPDR 组和PDR组患者血清RBP4 水平分别为（18.76±5.17）、（25.33±4.68）、（31.57±5.98）mg/L,与对照组[（11.65±4.32）mg/L]比较,差异有统计学意义（P＜0.05 或0.01）;NPDR 组、PDR组患者血清RBP4水平高于NDR 组,差异有统计学意义（P＜0.05 或0.01）。相关分析显示血清RBP4 水平与BMI、hs-CRP、TG 及HOMA-IR 呈显著正相关（r= 0.714、0.837、0.796、0.801,均P＜0.05）,多元逐步回归分析显示hs-CRP 和HOMA-IR 显著影响RBP4 水平（P＜0.05）。结论 血清RBP4 在糖尿病患者中显著升高,其水平变化与DR 的发生、发展密切相关。     

西藏那曲与北京郊区对流层气溶胶的微脉冲激光雷达测量

用微脉冲激光雷达对西藏那曲地区和北京郊区2004年夏季大气对流层气溶胶的光学特性进行了测量和分析，给出了两地区气溶胶消光系数的垂直分布以及那曲地区的大气边界层高度.结果表明:北京郊区大气对流层气溶胶的组分、浓度及粒径分布较那曲地区呈现出较大的不均匀性，那曲地区则具有较好的近地面空气质量.因此，利用微脉冲激光雷达可以实现大气气溶胶的有效测量.     

用软刻蚀方法制备PbS纳米晶复合聚丙烯酸微图形

利用软刻蚀方法制备了包裹有硫化铅纳米颗粒的聚丙烯酸微图形 .首先通过毛细微模塑法制备了丙烯酸铅的微条纹 ,并使之在γ射线引发下固态聚合 ,最后用硫化钠溶液处理聚合物微条纹 ,将铅离子转化为包埋在聚合物体系中的硫化铅颗粒 ,得到了包裹有硫化铅纳米颗粒的高清晰度的聚丙烯酸微图形 .利用X射线衍射(XRD)、X射线光电子能谱仪 (XPS)、透射电镜 (TEM)对其结构和性质进行了表征 .结果表明包埋在聚合物体系中的PbS颗粒直径小于 2 0nm .     

LNG球形贮罐绝热计算

分析了贮罐绝热体的传热规律,并建立了模型。通过近似理论计算得到了通过绝热体的传热量;利用计算软件对绝热体内传热过程进行了有限元计算,获得了通过贮罐绝热体的传热量以及绝热体内温度场的分布。以传热量为基准,将近似理论计算与有限元计算结果进行比较,表明有限元计算结果更为准确。     

Amorphous/2H-MoS2 nanoflowers with P doping and S vacancies to achieve efficient pH-universal hydrogen evolution at high current density

Science China Chemistry - Molybdenum disulfide (MoS2) has become a competitive candidate for efficient and economical hydrogen evolution reaction (HER). Compared with 1T-MoS2, 2H-MoS2 possesses...     

Li-Ga液态金属电池界面反应过程的原位检测

采用A型扫描超声脉冲反射技术, 对40 ℃ Li-Ga液态金属电池放电过程进行实时原位检测. 通过辨识正极界面超声信号指纹区, 发现正极界面的回波声压随液态金属电池放电容量的增加而增大, 表明放电产物Li₂Ga₇的声阻抗大于液态金属Ga; 当放电产物Li₂Ga₇完全覆盖正极表面时, 正极界面的回波声压较初始状态增大约45%； 归纳了不同放电阶段超声回波声压随放电容量的变化规律, 提供了判断电池状态的依据. 采用全聚焦相控阵超声三维成像技术, 对放电产物Li₂Ga₇在正极界面的形成过程进行可视化分析, 发现放电产物优先在正极界面中心区形成并聚集, 与放电1.4 mA·h的光学成像结果吻合, 揭示了Li-Ga液态金属电池放电过程中正极界面的传质特性. 总结归纳了超声回波信号与电池放电容量间的耦合关系, 建立了定量分析的工作曲线, 发展了一种液态金属电池正极界面过程原位无损检测的新方法.     

Evaluation of electrical characteristics of biological tissue with electrical impedance spectroscopy

The electrical characteristics of biological tissue is evaluated by establishing an electrical equivalent circuit with electrical impedance spectroscopy. The least squares method is used to realize electrical equivalent circuit fitting by using the developed portable electrical impedance spectroscopy system. The EIS system is used to obtain the impedance spectrum data of the measured biological tissue. In the experiment, the impedance spectrum data of eggs under different heating time were measured, and the established equivalent circuit model of eggs was fitted by nonlinear least squares fitting algorithm. Moreover, the electrical characteristics of the biological tissue are also revealed by numerical simulation with HANAI model. The experimental and simulation results show that the extracted equivalent electrical parameters can clearly characterize the variation of the internal change of components of biological tissues.     

Self-Supported ZIF-Derived Co3O4 Nanoparticles-Decorated Porous N-Doped Carbon Fibers as Oxygen Reduction Catalyst

Oxygen reduction is a significant cathodic reaction in the state-of-art clean energy devices such as fuel cell and metal–oxygen battery. Here, ZIF-incorporated hybrid polymeric fibres have been fabricated by using a dual-phase electrospinning method. These are then transformed into Co₃O₄-nanoparticle-decorated porous N-doped carbon fibres (ZIF-Co₃O₄/NCF) through multi-step annealing treatment. The resultant ZIF-Co₃O₄/NCF is interweaved into a self-supported film and can be used as a bi-functional catalyst for catalysing oxygen reduction in both aqueous and non-aqueous electrolytes. Electrochemical tests demonstrate that ZIF-Co₃O₄/NCF displays a high catalytic activity for oxygen reduction with a half-wave potential (E_1/2) of 0.813 V (vs. RHE) and an almost favourable four-electron reduction pathway in alkaline medium. ZIF-Co₃O₄/NCF catalyst only shows 4 mV negative shift of E_1/2 after 5000 continuous CV cycles. In addition, the ZIF-Co₃O₄/NCF can be applied as the cathode catalyst of non-aqueous Li–O₂ battery, exhibiting a remarkable ORR activity in LiPF₆ contained 1,2-dimethoxyethane electrolyte. The excellent electrocatalytic performance of ZIF-Co₃O₄/NCF is probably due to the abundance of active sites of graphitic carbon-wrapped Co₃O₄ nanoparticles, as well as the cross-linked fibrous nitrogen-doped carbon texture.     

Stability optimization of channel-interleaved photonic analog-to-digital converter by extracting of dual-output photonic demultiplexing

We investigate a channel-interleaved photonic analog-to-digital conversion(PADC)system’s ability to work stably over a long duration with an optimal driving voltage.The influence of optimum bias point drift of a Mach–Zehnder modulator(MZM)-based photonic switch on this system was analyzed theoretically and experimentally.The feasibility of extracting feedback signals from the PADC system was derived.A high-stability channel-interleaved PADC was constructed by extracting a feedback signal from a parallel demultiplexing module to control the MZM-based photonic switch’s driving voltage.Consequently,the amplitude mismatch between the channels was limited to within 0.3 d B over 12 hours of operation.