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为了在改善壳聚糖(CS)抑菌性能的同时提高其强度, 将银基蒙脱土(Ag-MMT)在CS的醋酸溶液中通过溶液插层法制备了银基蒙脱土/壳聚糖(Ag-MMT/CS)。在模拟体液环境中测得的银离子释放性能显示Ag-MMT/CS中的银离子可以达到平稳缓慢释放; 通过最小抑菌圈法对Ag-MMT/CS进行抑菌性能测试, 结果表明, Ag-MMT/CS对金黄色葡萄球菌有良好的抑菌效果, 抑菌圈直径可达9.2 mm, 比CS增大50.6%, 抑菌率测试结果显示蒙脱土的加入有助于吸附并杀死更多的细菌; 动态热机械分析(DMA)测试结果显示, Ag-MMT/CS的储能模量最高可达3261 MPa, 比CS提高195%, 显示出良好的动态力学性能。 相似文献
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在二醛基纳米纤维素悬液中加入银氨溶液原位合成载银纳米纤维素(Ag/DNCC),以壳聚糖(CS)为成膜基底,甘油为增塑剂,加入Ag/DNCC共混流延制备载银纳米纤维素-壳聚糖(Ag/DNCC-CS)复合膜。FT-IR和XRD测试结果表明Ag/DNCC的加入没有改变CS的分子结构和结晶状态,热性能测试结果表明Ag/DNCC对提高CS的热稳定性能不显著。添加Ag/DNCC后,SEM测试结果表明Ag/DNCC-CS复合膜微观形貌致密,拉伸强度比纯CS膜提高。Ag/DNCC含量为10%(wt,质量分数)制得的Ag/DNCC-CS复合膜的拉伸强度达到72.36MPa,对大肠杆菌和金黄色葡萄球菌均有较好的抑菌效果。 相似文献
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仿生矿化的镁合金降解和抑制金黄色葡萄球菌性能研究 总被引:1,自引:0,他引:1
通过对壳聚糖(CS)进行改性,成功制备了壳聚糖季铵盐(HACC)。经过FT-IR、1 H NMR表征,证实了其分子结构。采用在仿生溶液中添加CS或HACC的方法,在微弧氧化前后的镁合金样品表面修饰得到4种不同的仿生涂层。利用SEM和XRD对涂层分析表明,仿生矿化后的镁合金表面为含有CaP/CS或CaP/HACC的复合涂层。降解实验表明,微弧氧化后仿生矿化的样品失重率小于微弧氧化前仿生矿化的样品;利用ICP测定释放的镁、铝离子浓度,发现镁离子浓度先升高后降低,铝离子浓度越来越小。抑菌实验结果表明,含有CaP/HACC比含有CaP/CS的复合涂层样品对金黄色葡萄球菌具有更明显的抑菌作用;对于仿生溶液中添加同样浓度的CS或HACC,微弧氧化后比微弧氧化前矿化的样品抑菌率高。比浊法测定显示,4种涂层在4d内均具有不同程度的抑菌效果,微弧氧化后的镁合金样品在添加有HACC的仿生溶液中矿化得到的涂层抑菌率最高。研究说明,改性后的HACC比CS具有更强的抑菌作用;微弧氧化后的样品具有更强的抗腐蚀能力和载药性能。 相似文献
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目的将具有抑菌性能和抗氧化活性的原花青素与壳聚糖共混制备一种高抗氧化性能且绿色环保的膜材料,以期用于食品包装。方法采用流延法制备不同质量比的壳聚糖/原花青素复合膜(CS-PC),测定其力学性能、阻隔性能、抑菌性能和抗氧化性能。结果通过对不同质量比(mcs∶mpc)CS-PC膜的厚度、溶解度和拉伸强度进行测试,确定了壳聚糖与原花青素的最佳质量比为40∶3。与壳聚糖原膜相比,CS-PC膜的溶胀度和溶解度显著下降,下降率分别为30.73%和59.90%,拉伸强度提高了29.94%。加入原花青素后,壳聚糖膜的抑菌性能和抗氧化性能得到大大提高,CS-PC膜对大肠杆菌和黑曲霉的抑菌性能分别提高了53.57%和28.82%,对金黄色葡萄球菌的抑菌性能提高不明显;原花青素加入量越大,CS-PC膜的抗氧化活性就越高,当mcs∶mpc=40∶3时,CS-PC膜的DPPH清除率达到了82.35%,相比于CS膜提高了2.4倍。扫描电镜结果表明原花青素小分子的加入使壳聚糖膜的内部结构变得致密,孔状结构得以改善。傅里叶红外光谱分析显示原花青素与壳聚糖之间主要通过氢键交联。结论添加适量的原花青素到壳聚糖溶液中,可以制备一种高抗氧化活性的食品膜,同时该食品膜具有良好的抑菌性能。 相似文献
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采用水热合成法对伊利石进行改性, 再通过微波辅助和紫外灯还原法制备了高载银量的纳米银/伊利石复合材料。利用X射线衍射(XRD)、红外(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和抑菌圈试验等方法研究了复合材料的结构、形貌及抑菌性能。结果表明, 改性后伊利石具有较高的载银量, 最高可达27.66%, 而且还原的纳米银在伊利石表面分布均匀。抑菌圈试验结果显示, 这种复合材料对金黄色葡萄球菌和大肠杆菌均有良好的抑菌效果, 最大抑菌尺寸分别达到5.68 mm和6.84 mm。 相似文献
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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. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
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.…… 相似文献
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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. 相似文献
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N.A. Odintsova N.V. Ageenko K.V. Kiselev N.M. Sanina E.Y. Kostetsky 《International Journal of Refrigeration》2006,29(3):387
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. 相似文献
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David R. Smith F. R. Fickett 《Journal of research of the National Institute of Standards and Technology》1995,100(2):119-171
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. 相似文献
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Fco. Javier Franco Pérez Marc Gener Moret 《Materials and Manufacturing Processes》2017,32(7-8):876-884
ABSTRACTThe 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. 相似文献
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《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献