Photophysical and conformation properties of luminescent-labeled star poly-2-isopropyl-2-oxazolines based on octa-<Emphasis Type="Italic">tert</Emphasis>-butylcalix[8]arene in solution

The synthesis of luminescent-labeled copolymers of octa-tert-butylcalix[8]arene with 8 poly-2-isopropyl-2-oxazoline arms is carried out. Each macromolecule involves one luminescent label of the anthracene structure located at the end of one of the arms. The luminescent properties of the copolymers in water and methanol are studied. It is shown that, in aqueous solutions, the formation of intermolecular aggregates with a hydrophobic core and a hydrophilic shell results in a new photophysical process of migration of electron excitation energy accompanied by a decrease in the solution luminescence polarization. The interaction of oxazoline arms with poly(methacrylic acid) via the mechanism of interpolymer complex formation implies a weakening of the efficiency of energy migration.     

Lithium Imide Synergy with 3d Transition‐Metal Nitrides Leading to Unprecedented Catalytic Activities for Ammonia Decomposition

Alkali metals have been widely employed as catalyst promoters; however, the promoting mechanism remains essentially unclear. Li, when in the imide form, is shown to synergize with 3d transition metals or their nitrides TM(N) spreading from Ti to Cu, leading to universal and unprecedentedly high catalytic activities in NH₃ decomposition, among which Li₂NH? MnN has an activity superior to that of the highly active Ru/carbon nanotube catalyst. The catalysis is fulfilled via the two‐step cycle comprising: 1) the reaction of Li₂NH and 3d TM(N) to form ternary nitride of LiTMN and H₂, and 2) the ammoniation of LiTMN to Li₂NH, TM(N) and N₂ resulting in the neat reaction of 2 NH₃?N₂+3 H₂. Li₂NH, as an NH₃ transmitting agent, favors the formation of higher N‐content intermediate (LiTMN), where Li executes inductive effect to stabilize the TM? N bonding and thus alters the reaction energetics.     

污泥厌氧水解/酸化的影响因素及研究进展

污泥厌氧水解/酸化作为一种新型的污泥处置技术,由于具有较好的处理效果,已逐渐成为环境化学研究领域的热点。本文综述了国内外污泥厌氧水解/酸化产酸的研究现状,重点阐述了营养物质在厌氧条件下的化学变化以及pH、温度、氧化还原电位、碳氮比(C/N)、泥龄(SRT)及表面活性剂等对污泥厌氧酸化的影响,对其研究进展进行综述,并指出了污泥厌氧水解/酸化产酸在污泥处置方向的可行性和应用前景。     

Multimedia friendly home wireless LANs

Home wireless local area networks (LANs) will carry diverse multimedia applications such as data, video, voice, and time sensitive control information. To enable quality delivery of such applications, these networks should incorporate an efficient quality of service (QoS) support mechanism. However, existing home wireless LANs do not provide support for multimedia applications. In this paper, we introduce our software based solution that provides QoS support for voice, video and data while using existing wireless home networks. The experimental results we have obtained provide evidence that our solution provides QoS support for multimedia applications.     

中国近海典型海区表观光学特性分析与研究

受陆源物质的输入、海底地形、季节性海流等多因素影响,中国近海水体的光学特性复杂,且部分要素有着明显的区域性和季节性的变化特点.利用“我国近海海洋综合调查与评价专项”中的光学调查资料,给出了以表观光学特性为主的中国近海水体分类的结果,分析了中国近海典型海区表观光学特性的主要要素的季节性和区域性的变化特点及其成因.     

A Novel Repairable Fountain Codes Scheme Based on Partial Duplication Technique

Wireless Personal Communications - Distributed storage system (DSS) is an emerging paradigm which provides reliable storage services for various source data. As the fault-tolerance scheme for DSS,...     

Characterization of oil-free and oil-loaded liquid-crystalline particles stabilized by negatively charged stabilizer citrem

The present study was designed to evaluate the effect of the negatively charged food-grade emulsifier citrem on the internal nanostructures of oil-free and oil-loaded aqueous dispersions of phytantriol (PHYT) and glyceryl monooleate (GMO). To our knowledge, this is the first report in the literature on the utilization of this charged stabilizing agent in the formation of aqueous dispersions consisting of well-ordered interiors (either inverted-type hexagonal (H(2)) phases or inverted-type microemulsion systems). Synchrotron small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM) were used to characterize the dispersed and the corresponding nondispersed phases of inverted-type nonlamellar liquid-crystalline phases and microemulsions. The results suggest a transition between different internal nanostructures of the aqueous dispersions after the addition of the stabilizer. In addition to the main function of citrem as a stabilizer that adheres to the surface of the dispersed particles, it has a significant impact on the internal nanostructures, which is governed by the following factors: (1) its penetration between the hydrophobic tails of the lipid molecules and (2) its degree of incorporation into the lipid-water interfacial area. In the presence of citrem, the formation of aqueous dispersions with functionalized hydrophilic domains by the enlargement of the hydrophilic nanochannels of the internal H(2) phase in hexosomes and the hydrophilic core of the L(2) phase in emulsified microemulsions (EMEs) could be particularly attractive for solubilizing and controlling the release of positively charged drugs.