迭代立方攻击及其应用

由于种种原因,实际分析中立方攻击通常无法找到相当数量的密钥比特线性表达式,基于迭代的思想,提出了一种迭代立方攻击方法。将其应用于55轮KATAN32算法,实验结果表明较之前的方法,该方法具有更小的数据复杂度和计算复杂度,攻击效果明显。     

Preparation and surface activity of modified soy protein

A series of novel surfactants have been prepared by the reaction of hydrolyzed soy protein with alkyl succinic anhydride. These novel surfactants exhibit excellent surface active properties including surface tension, foaming, emulsifying, wetting power, and buffer ability. The hydrophobic modified protein exhibit more surface activity than original protein because of the enhanced hydrophobicity in structure. The increase in hydrophobic chain length leads to an increase in the surface activity. The surface tension reduction is correlated to the hydrophobicity of the modified molecule, which was determined by a fluorescent probe. In application on cotton bleaching procedures, these surfactants increase the whiteness of fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3498–3503, 2006     

Zeolite‐catalyzed isomerization of oleic acid to branched‐chain isomers

Branched‐chain (bc) saturated fatty acids (SFA) have potential as oleochemical intermediates since they have better oxidative stability than linear unsaturated fatty acids (UFA) and have better low‐temperature properties than linear SFA. Previous studies in converting UFA to bc‐FA using clay catalysts have resulted in only modest yields and conversions. Recent reports, however, have suggested that certain zeolites can be effective catalysts for converting UFA to bc‐FA in higher yields and conversions. In this work, we examined the scope and potential of the zeolite‐catalyzed synthesis of bc‐FA starting from readily available monounsaturated linear FA. Our results show that common UFA such as oleic acid can be converted to bc‐isomers using modified Ferrierite zeolite catalysts with high conversions (98%) and high selectivity (85%) and that the zeolite catalysts are reusable for at least three cycles. The positions of branching (methyl) on the FA chain were determined from the GC‐MS spectra of the picolinyl esters of the bc‐FA.     

高温下煤焦气化反应特性(Ⅰ)灰分熔融对煤焦气化反应的影响

在900～1500℃灰分的熔融温度范围内和常压下,研究了煤焦与二氧化碳的气化反应。实验研究发现,活化能随气化过程而变化,除反应初期外,气化反应严重受内扩散过程的影响。高温下的煤焦气化存在一个特性温度,在该温度下,反应中、后期气化速率显著降低,其影响范围在特性温度上下约200～300℃。特性温度与煤种及灰分性质等因素有关,一般低于其相应灰分的软化点温度。     

两种高压直流电源的比较及在铜冶炼烟气制酸装置电除雾器中的应用

论述恒压源与恒流源两种高压直流电源的工作原理和技术特点.对两种电源常见故障的原因进行分析，提出相应的解决方法。介绍两种电源在230kt／a诺兰达炉冶炼烟气和270kt／a转炉冶炼烟气制酸装置的电除雾器中的使用情况.     

PVC用ACR加工助剂的作用

简要介绍了ACR加工助剂发展历史及其改进PVC加工性能的作用，包括对PVC的离模膨胀、熔体破裂、熔体粘度和融化的影响。并讨论了不同生产商的ACR加工助剂及其在PVC中的不同用途。     

正交法在PTA生产中粒径控制上的应用

介绍了正交试验法在PTA生产中粒径控制上的应用。对第一、二结晶器采用L9( 34)正交表进行试验 ,选出最优操作方案为第一结晶器液位为 2 6 %、压力为 3 6 0 0kPa ,第二结晶器液位为 45 .5 % ,压力为 2 40 0kPa ,结果是 :平均粒径从原来的 ( 118± 10 ) μm控制到 ( 118± 8) μm左右 ,粒径小于 45 μm的从原来的 2 0 %下降到 15 %左右 ,粒径 2 5 0 μm以下的由 93 %上升到95 %左右     

Interactions between Cytochrome c and DNA Strands Self-Assembled at Gold Electrode

In this work, we reported the investigation on the interaction between DNA strands self-assembled at gold electrodes and an electron transfer protein, cytochrome c. We observed that cytochrome c exhibited well-defined electrochemistry in both double-stranded and single-stranded DNA films. This suggested that the electron transfer reaction of cytochrome c arose possibly due to the electron hopping along DNA strands rather than wiring along the double helix. We also compared the heterogeneous electron transfer rate of cytochrome c with that of a ruthenium complex, which further confirmed this mechanism.     

重组铜绿假单胞菌外毒素A工程菌发酵及表达产物的纯化

目的建立稳定、高效表达重组铜绿假单胞菌外毒素A(rEPA)的工程菌发酵及表达产物纯化工艺。方法规模化发酵表达rEPA的重组大肠杆菌rPE553D,离心收集菌体,渗透压调解使菌体周质间隙蛋白释放后,高速离心收集蛋白溶液。经DEAESepharoseFF、PhenylSepharose6FF疏水层析和SOURCE30Q强离子交换层析,超滤浓缩纯化rEPA。用HPLC、SDS-PAGE和Westernblot等方法检定生化和免疫学特性,并用小鼠和Vero细胞检定毒性。结果每55L培养基中rEPA产量超过4g,纯度在95%以上,细胞毒性降低了至少32000倍。其余各项指标均符合《中国生物制品规程》要求。结论已建立了收率高、纯度好、稳定、适合规模化生产rEPA的工艺。     

Phase Behavior and Mechanical Properties of Siloxane-Urethane Copolymer

Two series of siloxane-urethane copolymers were prepared from polydimethylsiloxane (PDMS) with a molecular weight of 1000 or 1800 which was used as a soft segment, 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (1,4-BD). Differential scanning calorimetry (DSC) demonstrated that the position (T_gs) and breadth (ΔB) of soft-segment glass transition of copolymers remained constant as the hard-segment content increased. Heat capacities at soft-segment glass transition of the copolymer (ΔCp) were 0.195∼0.411 J/g^○C and heat capacities of pure PDMS (ΔCp₀) were 0.571∼0.647 J/g^○C, leading to the various ΔCp/ΔCp₀ ratios. The ΔCp/ΔCp₀ ratios decreased as the increasing of hard-segment content, showing poor phase separation. The FTIR spectrum confirmed the occurrence of hydrogen bonding in ether end-group of pure PDMS. The ether group of the soft segment led to interfacial mixing between soft and hard segments. The tan δ of the soft segment determined by dynamic mechanical testing (DMA) also identified the mixing of soft and hard segments. The mechanical properties of the copolymer were directly related to either the soft and hard segment contents or the chain lengths of soft and hard segments. The hard segment that reinforced the soft segment and interfacial thickness between soft and hard segment dominated the mechanical properties.