股市为什么总让我失望

我是一个老股民，1993年开始炒股。但一轮一轮的牛市都没赚过钱，因为每次牛市来的时候，我手里都有一把熊市套着的股票，到了解套的位置就赶紧跑了。也许是心理素质不太好，每次股市跌的时候我都紧张，总想卖股票，但因为赔着钱又迟迟没卖，涨的时候又不敢追高，以至于机会一次次失去。     

High-efficiency focusing grating coupler with optimized ultra-short taper

A novel high-efficiency focusing non-uniform grating coupler is proposed to couple light into or off silicon photonic chips for large-scale silicon photonic integration. This kind of grating coupler decreases the transition length of the linking taper between the grating and the single-mode waveguide by at least 80%. The radian of the grating lines and the size of the taper are optimized to improve the coupling efficiency. An experimental coupling efficiency of ~ 68% at 1556.24 nm is obtained after optimization and the whole size of the grating is 12 μm × 30 μm, with a very short taper transition of ~15 μm long.     

A mini-review on econophysics:Comparative study of Chinese and western financial markets

We present a review of our recent research in econophysics, and focus on the comparative study of Chinese and western financial markets. By virtue of concepts and methods in statistical physics, we investigate the time correlations and spatial structure of financial markets based on empirical high-frequency data. We discover that the Chinese stock market shares common basic properties with the western stock markets, such as the fat-tail probability distribution of price returns, the long-range auto-correlation of volatilities, and the persistence probability of volatilities, while it exhibits very different higher-order time correlations of price returns and volatilities, spatial correlations of individual stock prices, and large-fluctuation dynamic behaviors. Furthermore, multi-agent-based models are developed to simulate the microscopic interaction and dynamic evolution of the stock markets.     

硅基光子集成研究进展

报道了国际上关于硅基光子集成的最新研究进展和本课题组在该领域的研究成果,包括对一些光收发模块、III-V族/硅基激光器等集成器件的结构改进和工艺的探索,展示了兼容互补金属氧化物半导体工艺的硅基光子集成在信息技术领域中的巨大前景.可以预见,硅基光子集成已成为硅光子学的主要研究内容,硅光子学及硅基光子集成的发展目标是趋向更高速率、更低功耗及更大集成密度.     

四边简支正交各向异性波纹型夹心矩形夹层板的固有频率

给出了一种把具有波纹型夹心的正交各向异性夹层板的控制方程组化为仅包含一个位移函数的单一方程的简单方法,从而获得了四边简支条件下其自由振动固有频率的精确解,同时还对两种具有重要实际意义的特殊情况进行了讨论。     

固体酸催化合成马来酸二辛酯

首次将铌酸用于催化合成马来酸二辛酯,在酐醇摩尔比1：3,回流反应1h,催化剂用量为5g/mol酐的条件下,转化率为99．3％,选择性为85．6％,催化剂不经处理,可循环使用多次,且不污染环境,相对于一些常见催化剂,具有明显的优点。     

聚苯乙烯我—1，2—亚乙基多胺树脂催化合成正丁基苯基醚

由氯甲基聚苯乙烯和多－1,2－亚乙基多胺反应合成了聚苯乙烯我－1,2－亚乙基多胺树脂,并通过质量变化,分析,交换量和红外光谱进行了表征,研究了利用该树脂催化合成正丁基苯基醚的反应,催化剂能够回收并重复使用,4次后其质量未损失,活性未下降。     

硫酸氢钠催化合成羧酸苄酯

讨论了一水硫酸氢钠催化合成乙酸苄酯的条件。羧酸、苄醇和硫酸氢钠的质量比为 3∶2∶0 .1 45 ,以环己烷为溶剂 ,进行回流分水 ,合成了甲酸苄酯、乙酸苄酯、丙酸苄酯和丁酸苄酯 ,其收率为 68.5 %～ 84.1 %     

硫酸氢钠催化合成羧酸烯丙酯

硫酸氢钠能够代替硫酸作为酯化催化剂。利用－水硫酸氢钠催化合成了甲酸烯丙酯、乙酸烯丙酯、丙酸烯丙酯、丁酸烯丙酯和戊酸烯丙酯,产物用折射率、元素分析和红外光谱表征。研究了硫酸氢钠用量对丙酸烯丙酯收率的影响。