Patterned self-adaptive polymer brushes by "grafting to" approach and microcontact printing

Patterned self-adaptive PS/P2VP mixed polymer brushes were prepared by "grafting to" approach combining with microcontact printing (muCP). The properties of the patterned surface were investigated by lateral force microscopy (LFM), XPS and water condensation figures. In the domains with grafted P2VP, the PS/P2VP mixed brushes demonstrated reversible switching behavior upon exposure to selective solvents for different components. The chemical composition of the top layer as well as the surface wettability can be well tuned due to the perpendicular phase segregation in the mixed brushes. While in the domains without grafted P2VP, the grafted PS did not have the capability of switching. The development and erasing of the pattern is reversible under different solvent treatment.

Stabilization of polymer bilayers by introducing crosslinking at the interface

Bisphenol A solid epoxy serves as an effective reaction compatibilizer to the bisphenol A polycarbonate (PC)/PMMA bilayer systems. Addition of epoxy to the bottom PMMA layer can retard or even prevent the dewetting of PC films by introducing crosslinking between both components at the interface. This is the first investigation of polymer bilayers stabilized by chemical reactions.

Synthesis using electrospinning and stabilization of single layer macroporous films and fibrous networks of poly(vinyl alcohol)

We demonstrated in this paper an electrospinning technique could be employed to prepare the single layer macroporous films and fibrous networks of poly(vinyl alcohol) (PVA). A crucial element using electrospinning on the development of these electrospun structures was to shorten the distance of from the needle tip to the collector (L), which resulted in the bond of the wet fibers deposited on the collector at the junctions. The morphologies and average pore size of electrospun structures of PVA were mainly predominated by L and the time of collecting wet fibers on the collector. In addition, experimental results showed that an increase of the PVA concentration or a decrease of the applied voltage could also diminish slightly the average pore size of electrospun productions. Furthermore, a 60 degrees C absolute ethanol soak to PVA electrospun production led them to be able to stabilize in water for 1 month against disintegration. Differential scanning calorimetry (DSC) demonstrated that the 60 degrees C ethanol soak enhanced the degree of crystallinity of PVA production. The structural characteristic of macroporous films and networks in combination with their easy processability suggests potential utility in issue engineering applications.

The stabilization effect of glutaraldehyde on the Spirulina plateusis phycobilisomes

The spectral properties of the glutaraldehyde-treated phycobilisomes were studied. The results showed that glutaraldehyde was effective in preventing phycobilisomes from dilution-induced dissociation and preserving the intra-phycobilisomes energy transfer.

Stabilization of Dynamic Systems for Multiple Omni-Directional Mobile Robots

本文考虑了由2个全方位移动机器人组成的混合动力学系统的协调拟镇定问题.利用机器人位置之间的向量与机器人目标之间向量的内积,设计了多步拟镇定律,该控制律能够在避碰后按指数速率运动到目标点,且在整个过程中两机器人之间的距离不小于避碰的安全距离.最后对2个全方位移动机器人进行了仿真,验证了所给方法的有效性。

Stabilization of Uncertain Nonholonomic Dynamic Systems with Bounded Inputs

The sliding mode approach and the multi-step control strategy are exploited to propose a stabilizing controller for uncertain nonholonomic dynamic systems with bounded inputs. This controller can stabilize the system to an arbitrarily small neighborhood about its equilibrium in a finite time .Its application to a nonholonomic wheeled mobile robot is described. Simulation result shows that the proposed controller is effective

冀东油田南堡滩海地区油气层损害机理与油气层保护方法研究及应用

Study and Application of Damage Mechanism and Protection Method of reservoir in Nanpu Shallow Beach Sea Area is one of the key research projects of Jidong Oilfield Company of PetroChina Company Limited from 2007 to 2008. Located at Nanpu Sag in Huanghua Depression of Bohaiwan Basin, Nanpu Shallow Beach Sea Area with 1000km2 exploration area posseses three sets, shallow Minghuazhen Formation and Guantao Formation of Upper Tertiary, middle-deep Dongying Formation of Lower Tertiary, deep Ordovician, of oil bearing series, according to the achievement of the connecting 3D seismic structure interpretation and the structural geological comprehensive research. Its main reservoir types include Upper Tertiary structural reservoir, Lower Tertiary structural and lithological-structural reservoir, and Ordovician ancient buried hill reservoir. How to protect reservoir, complete well and lift high efficiently is the key to realize high and stable yield of the oil wells during drilling, completing well, testing and repairing well. It is important for reservoir protecting during drilling that directly relate to efficient exploration. Therefore, beginning with basic characteristics and sensitive analysis of reservoir, study of reservoir damage machinism and analysis of reservoir damage potential factor are emphasized when prediction analysis about three-pressure profiles is carried out. The study both of physical and chemical properties and of the strata of the technology of borehole stabilization and reservoir protecting are outstanding. As the conclusions follow: （1）Based on the laboratory experiment about basalt cores, prediction of three- pressure profiles about 30 wells on No.1 and No.2 structure is practiced. The laws of plane pressure distribution are analyzed. （2）According to the analyses about reservoir feature data and about sensitivity evaluation to damage factor in Nanpu oil field, the scheme of reservoir protecting to the sand reservoir of Guantao Formation and the first section of Dongying Formation is put forward. （3）On basis of the analyses on lithological characteristics, mineral compositions, clay minerals, electrical behavior features, physical and chemical properties of basalt of Guantao formation in No.1 and No.2 structure, instability mechanism of basalt sidewall and technical countermeasures are obtained. （4）Aiming at the characteristics of Ordovician dissolution-pore fracture type carbonate reservoir, the scheme of the reservoir protecting to Ordovician is put forward. Creative study of the film forming and sealing and low invasion reservoir protection drilling fluid are successful. In summary, through the study of reservoir heterogeneity and sensitivity, a set of technology and schemes of reservoir protecting is put forward, which is adaptive during drilling the target bed in the research area and establishes the base for efficient exploration. Significant effect has showed in its application in Nanpu oil field.