Efective Error-Tolerant Keyword Search for Secure Cloud Computing简

The existing solutions to keyword search in the cloud can be divided into two categories： searching on exact keywords and searching on error-tolerant keywords. An error-tolerant keyword search scheme permits to make searches on encrypted data with only an approximation of some keyword. The scheme is suitable to the case where users＇ searching input might not exactly match those pre-set keywords. In this paper, we first present a general framework for searching on error-tolerant keywords. Then we propose a concrete scheme, based on a fuzzy extractor, which is proved secure against an adaptive adversary under well-defined security definition. The scheme is suitable for all similarity metrics including Hamming distance, edit distance, and set difference. It does not require the user to construct or store anything in advance, other than the key used to calculate the trapdoor of keywords and the key to encrypt data documents. Thus, our scheme tremendously eases the users＇ burden. What is more, our scheme is able to transform the servers＇ searching for error-tolerant keywords on ciphertexts to the searching for exact keywords on plaintexts. The server can use any existing approaches of exact keywords search to search plaintexts on an index table.     

Amphiphilic segmented polymer networks based on poly(2-alkyl-2-oxazoline) and poly(methyl methacrylate)

Amphiphilic segmented polymer networks (SPNs) have been prepared by free radical copolymerization of methyl methacrylate with α,ω-bisacrylate terminated poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline). DSC and DMTA analysis demonstrated the influence of the copolymer composition, the molecular weight and nature of the poly(2-alkyl-2-oxazoline)s and the polymerization conditions on the final phase morphology of the networks. A comparative phase morphology study of the polymer blends and SPNs revealed the more compatible phase morphology of the networks. The compatibility could be further increased by UV-induced network formation. The investigation of the solvent uptake in different solvents clearly demonstrated the amphiphilic nature of the SPNs.     

氧化焰烧成铜红釉

本研究以SiC作还原剂，采用氧化焰烧成，试制成功了在1250～1260℃下烧成的铜红釉，克服了传统的还原焙烧成方法的不足，简化了生产工艺，提高了铜红釉的成品率。     

Influence of epoxy resin on the morphological and rheological properties of PBT/ABS blends compatibilized by ASMA

Polybutylene terephthalate (PBT)/acrylonitrile–butadiene–styrene (ABS) copolymer blends compatibilized by a mixture of styrene–acrylonitrile–maleic anhydride (ASMA) copolymers and epoxy resin (EP) were prepared through melt reactive extrusion. The morphological, rheological, and mechanical properties of these blends were studied. The epoxy functional groups of EP can react with anhydride groups of ASMA and the PBT terminal groups (? OH and ? COOH) simultaneously, leading to the formation of ASMA–EP–PBT graft copolymers. Because of the effective compatibilization of these copolymers at the interface, finer dispersed phase morphologies were obtained. Compared with PBT/ABS/ASMA blends, the addition of EP induced a more stable molten phase structure, with increases of storage moduli, loss moduli, and dynamic viscosities. Results indicated that 1.5 wt% of the EP in the blends was most suited for the compatibilization. Impact properties of these blends were also investigated. POLYM. ENG. SCI., 47:1943–1950, 2007. © 2007 Society of Plastics Engineers     

一次低烧SrTiO3基晶界层电容器的研究

研究了以Ｌｉ２ＣＯ３为助烧结剂、Ｓｒ（Ｌｉ１／４Ｎｂ３／４）Ｏ３为施主掺杂剂、Ｂｉ２Ｏ３和ＳｉＯ２为晶界绝缘剂的ＳｒＴｉＯ３基晶界层电容器的一次低温烧成技术。初步探索了Ｔｉ／Ｓｒ比值、施主掺杂剂、绝缘剂对显微结构及介电性能的影响。在１１５０℃烧成温度下，获得了εａｐｐ〉３．５×１０＾４；ｐ〉１．０×１０＾１１Ω·ｃｍ；ｔｇδ〈１．０％；ΔＣ／Ｃ〈±５．０％（－２５￣＋８５℃）的ＳｒＴｉＯ３基晶界层     

利用广西气刀土原料研制高档卫生陶瓷

在对广西气刀土原料性能研究的基础上,进行了在卫生陶瓷坯料、釉料中的应用研究。坯料中加入4%～7%的广西气刀土原料替代等量的2#苏州土,在釉料中引入4～6%的气刀土原料替代1#苏州土,可以生产出理化性能和外观质量达到了美国ASMEA112.19.2M-1998标准要求的高档卫生陶瓷产品。引入广西气刀土原料使泥浆性能增强、厚化系数降低、湿坯硬度特别是内硬度明显提高、干坯抗折强度增大;制品体积密度增加、气孔率和吸水率降低;增强釉面乳浊效果、提高釉面白度,保证和提高产品的热稳定性能。     

Mobile phase composition for resolving whey proteins in reversed-phase high performance liquid chromatography

Reversed-phase high-performance liquid chromatography was successfully developed for the simultaneous and rapid separation for the main whey proteins, α-Lactalbumin and β-Lactoglobulin. This method consisted of a linear gradient of the two mobile phases of 0.1% trifluoroacetic acid in water and 0.1% trifluoroacetic acid in acetonitrile. The total run time for this separation was approximately 30 min, and α-Lactalbumin was eluted followed byβ- Lactoglobulin. The injection volume was fixed at 20 μl and the flow rate was 1 ml 1/min. The optimum mobile phase composition and gradient conditions to separate α-Lactalbumin and β-Lactoglobulin (A+B) were experimentally obtained at the 15 μm particle with a pore size of 300 Å on the linear-gradient mode.     

Foaming and chain extension of completely biodegradable poly(propylene carbonate) using DPT as blowing agent

Completely biodegradable foams of poly(propylene carbonate) (PPC) derived from carbon dioxide and propylene oxide were fabricated using N, N′-dinitroso pentamethylene tetramine (DPT) as chemical blowing agent, and urea as the activator to lower the decomposition temperature of DPT. Thermal decomposition behavior and gas evolution behavior of the DPT composite with various urea to DPT ratios were investigated to optimize the composition of the blowing agent. The formulation of blowing agent mixture and foaming condition, the foam morphologies, the molecular weight change, as well as the mechanical properties of produced PPC foams were studied extensively. The experimental results demonstrated that the greatest blowing ratio of 14.8 can be afforded in case 12 phr blowing agent was used at 170 °C for 30 min. Gel permeation chromatography (GPC) and thermal analysis revealed that DPT acted as both chain-extension agent and blowing agent for PPC matrix. The molecular weight of PPC subjected to foaming increased by 76%. The foamed PPC exhibited superior mechanical properties and can be used as packaging material for many practical applications.     

磺化聚芳醚酮酮催化合成顺丁烯二酸二丁酯

以交联的聚芳醚酮酮和20％发烟硫酸合成了磺化聚芳醚酮酮树脂，并用于顺丁烯二酸酐和正丁醇的催化酯化，最佳条件：醇：酐为2．5：1（物质的量比）；催化剂用量为2．5g，反应温度140－150℃，反应时间7h ，酯化率96．4％。气相色谱分析结果：顺丁烯二酸二丁酯的含量达99．96％，催化剂易回收且可重复使用。     

Synthesis of chaoite-like macrotubes at low temperature and ambient pressure

Chaoite-like carbon was prepared by quenching the pyrolysate of acetylene gas at 873 K and ambient pressure. Its morphology is carbon macrotubes (CMTs) with 20–60 μm in diameter and up to 8 mm in length. Microstructure analysis revealed that sp-bonded carbon (SPBC) chains in CMTs are kinked and the crystal orientation is anisotropic along the length and circumference directions of CMTs. A SPBC belt scrolling model was proposed for explaining the formation process of CMTs.