基于路由器编码的自适应包标记

拒绝服务攻击由于其高发性、大危害、难防范而成为因特网上的一大难题.研究人员为此提出了各种各样的对策,其中概率包标记具有较大的潜力.然而,现有的标记方案都存在各种各样的缺点.提出了一个新的标记方案,与其他标记方法相比,该方案具有反映灵敏,误报率低和计算量小的优点.此外,该方法还限制了攻击者伪造追踪信息的能力.

磁性纳米颗粒负载催化剂的制备及其在有机合成中的应用

过去的几十年，纳米科学在材料、医药、生物、催化等领域得到极其广泛的应用。由于在尺寸上的优势，使用纳米材料作为催化剂载体，可以使异相催化剂均相化，从而提高催化剂的活性和选择性。近年来，磁性纳米颗粒由于其容易分离的特点而作为催化剂载体受到广泛关注。鉴于此，本论文着眼于设计合成一系列磁性纳米颗粒负载的催化剂并研究其在一些有机化学反应中的应用，并进一步研究其重复使用情况。 本论文的主要内容包括以下几个部分： 1．制备了一系列磁性纳米颗粒固载的季胺盐和季膦盐，并将其应用到由二氧化碳和环氧化合物制备环状碳酸酯的反应中，详细研究了温度、催化剂用量、压力等条件对反应的影响，并进一步研究了催化剂的分离和重复使用情况。 2. 合成了二（2－吡啶基）－甲醇，通过Click反应将其固载到磁性纳米颗粒表面并与Pd进行配位，并将其应用于Suzuki和Sonogashira交叉偶联反应中，研究了不同溶剂和反应条件对反应的影响，并讨论了该催化体系的重复利用性能。 3. 合成了一系列的树枝状大分子负载的Click型有机催化剂，并将其用于酮对芳香硝基乙烯化合物的不对称Michael加成反应中。分别研究了在水相和无溶剂条件下反应进行的情况，并研究了催化剂的重复使用情况。 4. 制备了一系列磁性纳米颗粒负载的树枝状大分子催化剂，并应用于环己酮对芳香硝基乙烯化合物的不对称Michael加成反应中。研究了树枝状大分子的代数对催化剂活性的影响，并讨论了催化剂的分离和重复使用情况。

软件发布机制体系结构研究

针对现有软件发布方式主要以开发者的角度进行软件开发后生命周期管理所存在的问题,提出了更为合理的以用户的角度进行软件开发后生命周期管理的思想,建立了一种新的软件发布机制体系结构。该发布机制试图解决如下问题:让用户透明地使用软件,即用户不需要显式地进行软件的安装、更新和卸载;支持软件的即点即用和使用态发布,使用态发布指安装了某软件的计算机可以作为该软件的发布源;使得系统重装后能够以较小的代价恢复到指定的状态点。最后,分析了软件动态更新和分布式软件系统发布所应解决的问题。

携带叠氮和氨侧基的脂肪族聚酯的合成和表征

含有功能侧基生物降解聚合物的制备在近几年中受到广大研究者的极大关注[1,2].目前已经通过环状碳酸酯与丙交酯(LA)和ε-己内酯(CL)等共聚的方法合成了带有羧基[3~5]和羟基[6,7]等的脂肪族聚酯,并在靶向载体、药物控释及组织工程方面得到了应用[2,8].但有关含侧链氨基的聚合物研究的报道很少,且主要集中在氨基酸NCA单体与LA的嵌段共聚方面[9,10],很少得到侧链氨基的无规共聚物.本文通过丙交酯(LA)与环状碳酸酯单体共聚的方法制备了一种侧链带有溴原子的脂肪族聚酯,并将溴原子用叠氮基团取代,通过Cu(Ⅰ)催化的Click反应将其氨基化,得到了侧链带有氨基的脂肪族聚酯.

Synthesis and characterization of functional poly(gamma-benzyl-L-glutamate) (PBLG) as a hydrophobic precursor

Four kinds of functional poly(gamma-benzyl-L-glutamate) (PBLG) copolymers containing chloro, azido, allyl or propargyl groups on the side chains were synthesized through ester exchange reactions of PBLG with functional alcohols without any protection and de-protection process. Hydrolysis of PBLG, which was found during the ester exchange reaction under low ratios of alcohol to the repeat units of PBLG, was thoroughly investigated, and could be successfully depressed by addition of certain amount of benzyl alcohol to the reaction system. Click chemistry reactions of the azidized or propargylated copolymers, thiol-ene reaction of the allyllated copolymer were taken successfully, indicating that the functional groups on the copolymers were still reactive.

Hemoglobin conjugated micelles based on triblock biodegradable polymers as artificial oxygen carriers

An artificial oxygen carrier is constructed by conjugating hemoglobin molecules to biodegradable micelles. Firstly a series of triblock copolymers (PEG-PMPC-PLA) in which the middle block contains pendant propargyl groups were synthesized and characterized. After the amphiphilic copolymer was self-assembled into core-shell micelles in aqueous solution, azidized hemoglobin molecules protected by carbon monoxide (CO) were conjugated to the micelles via click reaction between the propargyl and azido groups. The conjugation causes an increase of the micelle's mean diameter. Maximum conjugation ratio is 250 wt% in the hemoglobin-conjugated micelles (HCMs). Oxygen-binding ability of the HCMs was demonstrated by converting the CO-binding state of the HCMs into O-2-binding state.

Macrocycle-Terminated Core-Cross-Linked Star Polymers: Synthesis and Characterization

We have synthesized macrocyclic polystyrene- (PS-) terminated PS star polymers via a core-cross-linking approach in this work. A tadpole-shaped macrocyclic PS-linear-PS copolymer was synthesized at first via click chemistry and ATRP polymerization method. The "living" ATRP initiating chain-ends of the tadpole-shaped copolymers were linked together via ATRP polymerization with divinylbenzene to form a core-cross-linked macrocyclic star polymer. The number of arms attached to the macrocyclic star polymers was measured with NMR. and absolute molecular weights with gel permeation chromatography (GPC) with multiangle laser light scattering detector. These macrocyclic star polymers had a highly cross-linked core and many radiating arms. The shorter tadpole-shaped precursors caused core-cross-linked star polymers with higher molecular weights and more arm numbers. The macrocycle-terminated core-cross-linked star polymers showed two glass transition temperatures, one arising from the linear branches and another from the macrocycles.

遮挡范式下碰撞时间估计的特性研究

The estimation of Time to Collision (TTC) related to avoiding collisions or making interceptions is an important cognitive ability for individuals. A number of studies have been carried out on this topic and related theories are developed. One of the most famous theories is the τ Theory. Based on the τ Theory, researches have found that visual information and physical information of moving objects would influent the TTC estimation. Are there any other factors that can affect people’s TTC estimation? A mixed design was used to examine the TTC estimation by different types of participants (professional drivers / people can not drive), with different moving objects (car/tricycle), under different speed (slow/fast) and direction (left to right / right to left) in Occlusion Paradigm. There were 21 professional drivers and 20 individuals who cannot drive participated in the experiment which was displayed on a computer. Participants were asked to click the button when he/she believed that the moving object had just contacted the red line. E-prime was used to establish the whole experimental environment and the RT was recorded at the same time. The results revealed that: (1) there is significant different TTC estimation between car and tricycle; (2) the professional drivers have more accurate TTC estimation than people do not drive. We can come to conclusion that conceptual information and driving skill could affect TTC estimation.