离子液体中壳聚糖的AGET ATRP改性及其抗菌性能研究

以壳聚糖为原料,2-溴异丁酰溴为反应试剂合成壳聚糖大分子引发剂CS-Br,并用其引发甲基丙烯酰氧乙基三甲基氯化铵(DMC)在离子液体BMIMCl中的电子活化再生原子转移自由基聚合(AGET ATRP),制备出壳聚糖季铵盐抗菌剂P(CS-Br-DMC)。采用环境扫描电镜(ESEM)、红外光谱(FT-IR)、透射电镜(TEM)等对产物结构进行表征,并对其抗菌性能进行研究。结果表明,通过AGET ATRP可成功合成壳聚糖季铵盐P(CS-Br-DMC),且聚合物在丙酮溶液中具有自组装行为;所制备的壳聚糖季铵盐对织物具有优良的抗菌性能,其抗菌效果明显优于未改性的壳聚糖。     

琥珀酰壳聚糖的制备及其与HL-60细胞亲和性的研究

以粘均相对分子质量700000和17500的高脱乙酰度壳聚糖为原料,通过吡啶催化制备N-琥珀酰壳聚糖(N-SUCC-CCTS),通过甲磺酸保护氨基制备O-琥珀酰壳聚糖(O-SUCC-CTS).应用异硫氰酸荧光素黄(FTTC)对合成的2种琥珀酰壳聚糖进行标记,荧光标记率分别为0.97%(O-SUCC-CTS)、0.66%(N-SUCC-CTS1.75)和0.34%(N-SUCC-CTS70).用流式细胞仪测定琥珀酰壳聚糖与人白血病HL-60细胞的结合能力,亲和性能力顺序为O-SUCC-CTS1.75＞N-SUCC-CTS1.75＞N-SUCC-CTS70.O-SUCC-CTS是一种很有潜力的抗肿瘤靶向载体.     

氨基酸改性壳聚糖抗菌材料制备及其性能研究

以壳聚糖(CS)为基体,在缩合剂1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC·HCl),偶联剂N-羟基-丁二酰亚胺(NHS)的存在下,将L-精氨酸接枝到CS大分子上,制备出一种天然高分子基重金属螯合及抗菌材料,L-精氨酸接枝壳聚糖CS-L-Arginine(CA)。阐述了反应机理,用采用元素分析、拉曼光谱(RAM)、核磁共振谱(13C NMR)以及X射线衍射谱(XRD)分析与表征了产物的结构产物。加入山梨醇作为增塑剂,采用涂膜法制备氨基酸改性壳聚糖膜。实验表明,随着接枝率的提高,改性壳聚糖膜对Ni~(2+)、Cu~(2+)的饱和吸附量的变化趋势先增大再减小,当接枝率为16.85%的改性壳聚糖膜对Ni~(2+)、Cu~(2+)的饱和吸附量达到最优,分别为148.32与198.78mg/g;对大肠杆菌和金黄色葡萄球菌的抑制作用逐渐提高,当接枝率为16.85%时,抑菌效率最佳,可分别达到了92.06%,93.58%。     

壳聚糖静电吸附羧基磷酰胆碱聚合物的研究

采用饥饿法聚合合成了3种不同配比的甲基丙烯酰氧乙基磷酰胆碱-甲基丙烯酸二元共聚物(poly(MPC-co-MA),PMA),并将其静电吸附在壳聚糖表面(CS-PMA)。通过动态接触角(DCA)对影响静电吸附改性的盐及聚合物组成因素进行研究。用X-射线光电子能谱(XPS)、原子力显微镜(AFM)对改性壳聚糖膜的表面元素组成、形貌进行表征,并通过血小板黏附实验对其抗凝血性能进行评价。结果表明,这种利用静电吸附的方式将磷酰胆碱聚合物吸附在壳聚糖表面,可获得具有仿细胞外层膜结构的涂层表面。与壳聚糖相比,改性后壳聚糖可以显著降低对血小板的黏附,抗凝血性能显著提高。该研究为构建仿细胞外层膜结构改善材料血液相容性提供了一种简单、便捷的方法。     

季铵化壳聚糖-聚乙烯醇阴离子交换膜的性能

碱性直接甲醇燃料电池(ADMFC)具有电极反应速率高,甲醇渗透率低的优点,阴离子交换膜是ADMFC的核心之一.以壳聚糖(CS)和环氧丙基三甲基氯化铵为原料合成季铵化壳聚糖,将其与聚乙烯醇(PVA)共混后制得一系列不同配比的季铵化壳聚糖(QCS)/聚乙烯醇阴离子交换膜,对膜的导电率和甲醇渗透系数进行了测试和分析.结果表明:季铵化壳聚糖与聚乙烯醇有较好的相容性,所制季铵化壳聚糖(QCS)/聚乙烯醇共混膜结构致密均匀,膜的吸水率和溶胀度随季铵化壳聚糖含量增大而减小,离子导电率随季铵化壳聚糖含量增大而提高,80℃时季铵化壳聚糖含量为60%的共混膜导电率最高可达2.5×10-2 S/cm.膜的甲醇渗透系数低于Nafion膜.     

单组分化学增幅型光致抗蚀剂LB膜的制备及光刻应用

合成了光致产酸剂N-对甲苯磺酸酯马来酰亚胺(TsOMI),及其与十二烷基甲基丙烯酰胺(DDMA)、对叔丁氧基苯乙烯碳酸酯(t-BOCSt)聚合得到三元共聚物。研究了该聚合物分子在气/液界面的成膜性,LB膜的光敏性和光刻性能。结果表明:该聚合物分子可在不同材质的基板上制备规整均匀的LB膜,在250nm紫外光照下,LB膜表现出化学增幅作用。以40层该聚合物LB膜为抗蚀层,经紫外曝光20min、显影10s后可得到分辨率为0.75μm(该掩膜所能达到的最大分辨率)的正型LB膜图形,进一步刻蚀得到分辨率为0.75μm的金膜图形。     

双胍化壳聚糖全互穿网络阴离子交换膜的制备及表征

以壳聚糖(CS)和双氰胺为原料,在一定温度下通过亲核加成合成壳聚糖双胍盐酸盐(CGH),并以三聚氰胺(MA)为交联中间体,戊二醛为交联剂制备具有全互穿结构的阴离子交换膜(CGH-MA)。对该系列膜进行了红外、热重分析以及力学性能等测试,并探讨了三聚氰胺含量对阴离子交换膜离子交换能力、导电能力以及耐碱稳定性的影响。实验结果表明,三聚氰胺含量为4%时,该膜的离子交换能力最高可达2.47 mmol/g,70℃电导率达到4.4×10~(-2)S/cm,该膜在60℃2 mol/L KOH溶液中浸泡192 h后,电导率未有明显变化,表现出优异的耐碱稳定性。     

ATRP可控接枝制备pH敏感性微滤膜

首先利用再生纤维素膜表面的羟基与2-溴异丁酰溴进行反应,引入原子转移自由基聚合(ATRP)所需的大分子引发剂,然后在膜表面可控接枝具有批pH敏感性的聚丙烯酸。通过X光电子能谱仪(XPS)、红外光谱测试(FT-IR),扫描电子显微镜(SEM)表征了膜的表面结构与形貌,证明已成功接枝上丙烯酸。采用膜通量测试研究了接枝膜对pH值的敏感性。实验结果证明,膜表面的接枝聚合具有一定可控性,pH敏感性的功能化可通过原子转移自由基聚合(ATRP)来设计。     

原子转移自由基聚合制备聚降冰片烯电解质

采用双(β-酮萘胺)镍(Ⅱ)、B(C6F5)3及AlEt3三元催化体系催化降冰片烯(NB)及5-降冰片烯-2-甲醇(NB-CH2OH)的加成聚合,合成聚(降冰片烯-co-降冰片烯基甲醇)(PNB-OH).通过PNB-OH与2-溴-异丁酰溴反应合成Br-PNB,以引发与对苯乙烯磺酸钠(SSA)或甲基丙烯酰氧丙基磺酸钾(S...     

改性壳聚糖及其膜材料的制备与表征

以壳聚糖(CS)、亚磷酸和多聚甲醛为原料,制备N-亚甲基磷酸化壳聚糖(NPCS)。利用红外光谱和核磁共振波谱表征其结构。CS和NPCS膜对Ca2+的络合性能表明,磷酸化改性的NPCS膜对Ca2+的络合能力大大提高,钙离子的行为与p H有关,络合量随p H值增加而增加,在p H为10时的络合过程符合一级动力学。X射线衍射分析表明磷酸化壳聚糖的结晶度下降,膦改性壳聚糖与Ca2+络合后结晶度提高。原子力显微镜和扫描电镜分析表明,NPCS膜表面较粗糙,有一些圆柱状突起,经钙化后NPCS膜的表面趋于平滑细腻,出现一定螺旋结构的树枝状网络突起,深度为275 nm,螺旋条纹间距约为200~400 nm,这种螺旋状的枝杈网络突起纵横交错在一起形成更厚更致密的覆盖层,使NPCS膜的表面平坦化。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.