A novel method to prepare water dispersible poly(benzimidazobenzophenanthroline) (BBL) by partial substitution of chain ends with poly(ethylene oxide)

Poly(benzimidazobenzophenanthroline) (BBL) was prepared according to literature method and modified with poly(ethylene oxide) in a one pot synthesis. After precipitation in aqueous sodium carbonate solution and subsequent purification, aqueous dispersions were prepared by ultrasonication. Particle sizes in the dispersions ranged from few tens of nanometers to several micrometers and most of the particles had sizes of 50–250 nm. Further studies indicated that the colloidal stability is a combined result of steric stabilization caused by excluded volume interactions of PEO chains on particle surface and electrostatic stabilization by the dissociated carboxylic acid groups on the particle surface. The product could be processed into uniform films 20–30 nm in thickness by spin coating onto gold-plated silicon substrates having aminethiol monolayer as the top most layer.     

D-spaces and thick covers

The following results are obtained.

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An open neighbornet U of X has a closed discrete kernel if X has an almost thick cover by countably U-close sets.

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Every hereditarily thickly covered space is aD and linearly D.

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Every t-metrizable space is a D-space.

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X is a D-space if X has a cover {Xα:α<λ} by D-subspaces such that, for each β<λ, the set ?{Xα:α<β} is closed.

     

Nature of bonding in group 13 dimetallenes: a delicate balance between singlet diradical character and closed shell interactions

The nature of metal-metal bonding in group 13 dimetallenes REER (E = Al, Ga, In, Tl; R = H, Me, (t)Bu, Ph) was investigated by use of quantum chemical methods that include HF, second order M?ller-Plesset perturbation theory (MP2), coupled cluster (CCSD(T)), complete active space with (CASPT2) and without (CAS) second order perturbation theory, and two density functionals, namely, B3LYP and M06-2X. The results show that the metal-metal interaction in group 13 dimetallenes stems almost exclusively from static and dynamic electron correlation effects: both dialuminenes and digallenes have an important singlet diradical component in their wave function, whereas the bonding in the heavier diindenes and, in particular, dithallenes is dominated by closed shell metallophilic interactions. The reported calculations represent a systematic attempt to determine the metal and ligand dependent bonding changes in these systems.     

MEMS助力推动下一代无线通信

未来的无线通信系统将具备各种新功能并高度微型化。而且,3代和4代多模/多波段无线终端设备将为新业务、互联网与Mcommerce(移动电子商务)数据、以及静态/视频图象提供网络连接。此外,终端设备也应具备更多新功能来吸引更多终端用户。微电子 机械(microelectromechanical,MEM)元件与系统可提高创新性3代产品的集成化水平,并可调整器件的特性和工作方式,因此可降低3代 图 产品的尺寸和成本。它们还将为 　　　无线系统带来新的体系结构和功耗管理特征。此外,MEMS还将推动新功能、传感器、执行器在无线终端设备上的集成。用户接口需要采用新的技术解决方案。微机械传感器和麦克风已经有元件形式的产品,它们可以被看作是更复杂、包括若干集成化传感器元件的智能系统的一个组成部分。对移动终端来说,娱乐和游戏功能是新功能开发的重要推动力,传感器和执行器也是如此。微反射镜和微透镜为照相机和显示器的实现带来了新的可能,如投影显示。因此MEMS将极大地促进未来无线系统的发展。本文将对 MEMS 在无线通信发展 中的应用进行探讨,首先讨论微系统 化、多功能器件在紧凑系统中的集成、...     

Componentwise adaptation for high dimensional MCMC

Summary  We introduce a new adaptive MCMC algorithm, based on the traditional single component Metropolis-Hastings algorithm and on our earlier adaptive Metropolis algorithm (AM). In the new algorithm the adaption is performed component by component. The chain is no more Markovian, but it remains ergodic. The algorithm is demonstrated to work well in varying test cases up to 1000 dimensions.     

Design of a Microprocessor Control System for a Solid-Fuel Water Boiler

A design of an industrial microcomputer control system for a 1.6-MW boiler using solid fuel is presented. Instrumentation and control philosophies for the boiler are discussed. The microcomputer system is based on standard iSBC microcomputer boards. The software consists of a real-time operating system RXM/80 and application tasks. The designed control system saves fuel and gives a more reliable over-all operation.     

Theoretical investigation of paramagnetic diazabutadiene gallium(III)-pnictogen complexes: insights into the interpretation and simulation of electron paramagnetic resonance spectra

The electronic structures and the spin density distributions of the paramagnetic gallium 1,4-diaza(1,3)butadiene (DAB) model systems [((t)Bu-DAB)Ga(I)[Pn(SiH3)2]]* and the related dipnictogen species [((t)Bu-DAB)Ga[Pn(SiH3)2]2]* (Pn = N, P, As) were studied using density functional theory. The calculations demonstrate that all systems share a qualitatively similar electronic structure and are primarily ligand-centered pi-radicals. The calculated electron paramagnetic resonance (EPR) hyperfine coupling constants (HFCCs) for these model systems were optimized using iterative methods and were used to create accurate spectral simulations of the parent radicals [((t)Bu-DAB)Ga(I)[Pn(SiMe3)2]]* (Pn = N, P, or As) and [((t)Bu-DAB)Ga[Pn(SiMe3)2]2]* (Pn = P or As), the EPR spectra of which had not been simulated previously due to their complexity. Excellent agreement was observed between the calculated HFCCs and the optimum values, which can be considered the actual HFCCs for these systems. The computational results also revealed inconsistencies in the published EPR data of some related paramagnetic group 13-DAB complexes.