Quantum speedup via engineering multiple environments

Evolution speed of an open quantum system is vividly influenced by the structure of environments. The strong system‐environment coupling is found to be able to accelerate quantum evolution. In this work, we propose a different method of governing the quantum speedup via engineering multiple environments. It is shown that, with a judicious choice of the number of coupling environments, the quantum speedup of an open system can be achieved even under weak system‐environment coupling conditions. The mechanism for the speedup is due to the switch between Markovian and non‐Markovian regions by manipulating the number of the surrounding environments. In addition, we verify the above phenomena by using quantum dots embedded in a planar photonic crystal under current technologies. These results provide a new degree of freedoms to accelerate quantum evolution of open systems. The strong system‐environment coupling can speed up the quantum evolution process. This work shows that, via engineering multiple environments, one can speed up the evolution process even under weak coupling conditions.     

Experimental investigation on a software synchronous optical sampling technique based on periodically poled lithium niobate

A software synchronous optical sampling system is constructed based on sum frequency generation (SFG) in periodically poled lithium niobate (PPLN). Five gigahertz of a non-return-to-zero (NRZ) data signal is sampled by sampling pulse with the repetition frequency of 29.31 MHz. The power of the SFG light is set at 23 dBm, and an eye diagram is successfully recovered. A band-pass filter is added before the sampling pulse is subjected to erbium-doped fiber amplifier to reduce gain competition and ensure a high power level of SFG.     

Banach空间的K—M逼近

设Ｘ是自反、严格凸且具有Ｈ性质的Ｂａｎａｃｈ空间，Ａ是Ｘ的弱序列完备子集。本文证明了Ａ是可逼近紧的Ｃｈｅｂｙｓｈｅｖ集的充分必要条件是Ａ是太阳集；同时，也讨论了Ｏｒｌｉｃｚ序列空间的太阳集。     

Orlicz序列空间的弱收敛序列系数

本文给出了Orlicz序列空间的弱收敛序列系数的表达式.     

Olicz空间L_M的L_N~°一致凸点

给出了Ｏｒｌｉｃｚ空间ＬＭ中Ｌ°Ｎ一致凸（Ｌ°ＮＵＲ）点的定义，找到了ＬＭ中Ｌ°ＮＵＲ点的判别准则及一些相应推论．     

二维正方晶格钨-硅橡胶声子晶体的带隙特性研究

本文利用平面波展开法和有限元法计算了二维正方晶格钨-硅橡胶声子晶体的能带结构,分析了弹性波在嵌有周期性排列的相同孔径的圆柱形钨块声子晶体结构中的传播特性.对能带结构中出现的特殊现象,例如狄拉克点以及狄拉克点附近的简并态等进行了分析.给出了三维能带图以及不同模式下的主要变形情况,发现在基体与散射体结合的部位容易出现应力集中的现象.同时讨论了复合材料的不同参数对带隙的影响,发现随着密度比(散射体密度与基体密度的比值)的增大,第一完全带隙的起始频率逐渐增加,但是截止频率变化较小,带宽逐渐减小.相对于杨氏模量比,密度比对带隙的影响更大.本文的结果将对实际的工程应用提供一定的理论指导.     

Weak orthogonality and weak property (β) in some banach sequence spaces

It is proved that a Köthe sequence space is weakly orthogonal if and only if it is order continuous. Criteria for weak property () in Orlicz sequence spaces in the case of the Luxemburg norm as well as the Orlicz norm are given.     

Weakly convergent sequence coefficient in Köthe sequence spaces

In this paper, we have discussed the weakly convergent sequence coefficient in Köthe sequence spaces with as their boundedly complete basis. Using those results, we can easily calculate the weakly convergent sequence coefficient in Orlicz sequence spaces.

     

Ex Vitro Expansion of Human Placenta-Derived Mesenchymal Stem Cells in Stirred Bioreactor

The high demand of human placenta-derived mesenchymal stem cells (hPDMSCs) for therapeutic applications requires reproducible production of large numbers of well-characterized cells under well-controlled conditions. However, no method for fast hPDMSCs proliferation has yet been reported. In the present study, the feasibility of using a stirred bioreactor system to expand hPDMSCs was examined. hPDMSCs were cultured either in stirred bioreactors or in tissue culture flasks (T-flasks) for 5 days. Total cell density and several parameters of physical microenvironments were monitored in the two culture systems every 24 h. The maintenance of the antigenic phenotype of hPDMSCs before and after culturing in the stirred bioreactor system was cytometrically assessed. Data suggested that the physical microenvironment in the stirred bioreactors was much more favorable than that of the T-flasks. At the end of 144 h culturing, the total cell number was increased 1.73 times from the T-flasks to the stirred bioreactors. In addition, hPDMSCs could maintain their antigenic phenotype when cultured in stirred bioreactors. These results provide the initial assessment for large-scale hPDMSCs production using suspension culture bioreactors.