新型生物降解交联剂的制备及其在壳聚糖交联膜中的应用

本文用聚乙二醇和丙交酯在辛酸亚锡的催化作用下合成了可降解的二羟基中间体,再与2,4-甲苯二异氰酸酯(2,4-TDI)反应,合成了异氰酸酯基封端的一系列生物降解型交联剂.并且对中间体和交联剂进行了 FTIR分析表征.应用交联剂对壳聚糖膜材料进行交联,并对交联材料进行了吸水率,表面接触角及力学性能的测定,结果表明新型生物降解交联剂的运用不仪改善了材料吸水性,也提高了材料的力学性能.     

双交联明胶-壳聚糖复合人工真皮支架的制备及其性能研究

采用1-乙基-(3-二甲基氨基丙基)碳化二亚胺盐酸盐(EDC.HCl)和三聚磷酸钠(STPP)作为共价-离子双交联剂交联制备了明胶-壳聚糖(gel-CS)复合人工真皮支架。通过FT-IR和SEM对复合多孔支架结构及形貌进行表征,同时对复合多孔支架的孔隙率、平均孔径、溶胀性能和降解性能进行了研究。研究结果表明,明胶和壳聚糖两相间成功地发生了交联反应,形成了具有贯通孔结构和良好孔隙率的复合多孔支架。该支架平均孔径在136.1～182.9μm之间,且随着壳聚糖含量的增加,孔径及孔隙率随之降低;溶胀性能研究发现,相较于单一共价交联方法,采用双交联法制备的支架溶胀率有所降低,再次印证双交联法制备的支架其交联度较单一共价交联的高;酶降解实验表明,固定STPP含量,随着EDC含量增加,复合支架的降解性能越好,而EDC含量一定,则STPP含量为0.5%时,复合支架具有最好的降解性能。     

壳聚糖膜在重金属处理中的应用研究

以壳聚糖为原料,制备了壳聚糖(CS)超滤膜、邻苯二甲酸二丁酯(DBP-C)壳聚糖多孔膜、壳聚糖/聚乙烯醇(CS/PVA)共混膜三种膜.通过综合运用原子吸收和红外光谱等技术研究交联剂的种类、剂量,对交联壳聚糖膜的物理化学性质与结构的关系及其对重金属离子Cd~(2+)、Pb~(2+)的吸附的影响,添加戊二醛、环氧氯丙烷交联剂对交联壳聚糖微球的影响及其对重金属离子Cd~(2+)、Pb~(2+)的吸附效果.结果表明,交联剂剂量和种类对有效去除重金属离子十分关键,红外光谱研究显示壳聚糖分子中带有的大量活性基团(-NH_2/-OH)与重金属离子配位形成金属螯合物去除了重金属离子;扫描电子显微镜结果表明交联壳聚糖膜在吸附重金属离子前后发生了显著变化,由光滑转变成粗糙.     

改性酰化壳聚糖缓释肥包膜材料的制备与表征

壳聚糖与辛酰氯酰化反应,制备低取代度的酰化壳聚糖。通过元素分析计算酰化壳聚糖的取代度,并用红外光谱、核磁共振、尿素渗透测试对其结构及渗透性能进行分析和表征。以戊二醛为交联剂,制备了一系列酰化交联壳聚糖膜,用吸水倍率、接触角、X射线衍射仪、热重分析、尿素渗透等对其性能进行分析表征。结果表明,交联使酰化壳聚糖热稳定性提高;酰化交联壳聚糖缓释包膜材料结晶度下降,疏水性提高;随戊二醛含量增加,尿素累积渗透量下降,7 d内尿素累积渗透量由74.7%降低至34.2%,28 d时尿素累积渗透量为76.7%,改性酰化壳聚糖膜缓释性能良好。     

可生物降解的壳聚糖肥料包膜材料的研究

以壳聚糖、聚乙烯醇、淀粉为原料，通过交联反应制备了可生物降解的壳聚糖肥料包膜材料，详细讨论了制备过程中的诸因素对膜性能的影响。结果表明，制备的薄膜的性能优于纯壳聚糖膜，可以用作缓释肥料包膜．     

交联壳聚糖膜对醇—水混合液的渗透汽化性能

在壳聚糖液中加入交联剂,制备出不溶性的交联壳聚糖膜。该膜对醇—水混合液具有良好的分离性能,对某些醇—水混合液可以达到一次性分离。交联剂用量对膜的性能有很大的影响,随着交联剂用量的增加,膜的溶胀度和吸水率下降,醇—水混合液的分离系数下降,渗透通量增大。关于温度和料液浓度对交联壳聚糖膜的渗透汽化性能的影响也作了研究。前文报道了醇—水混合液通过壳聚糖膜的渗透汽化分离性能。虽然壳聚糖膜对醇—水混合液具有良好的分离性能,但它在低醇含量的水溶液中,溶胀度较大,膜的尺寸稳定性差。为了提高膜的尺寸稳定性,我们制备了交联壳聚糖膜,对其渗透化性能进行了研究。     

乙二醛交联壳聚糖树脂对Cu(Ⅱ)吸附研究

以乙二醛为交联剂,由壳聚糖合成了一种交联壳聚糖树脂.研究了不同温度下其对Cu(Ⅱ)的静态吸附性能,测定了不同温度下的吸附曲线,并通过FTIR及XRD对交联壳聚糖树脂产物和吸附Cu(Ⅱ)后的材料结构进行了表征.结果表明,乙二醛交联壳聚糖树脂在40℃时对铜离子的平衡吸附量为78mg/g,不同温度下的吸附过程符合一级动力学模...     

多孔壳聚糖交联树脂的制备及对磷酸盐中磷的吸附

以壳聚糖为原料,二甲苯为分散剂、乙酸乙酯为致孔剂、环氧氯丙烷为交联剂,利用反相悬浮交联法制备了多孔壳聚糖交联树脂;通过红外光谱对树脂结构进行表征并对其性能参数进行了测定;系统考察了该多孔树脂对磷酸盐中磷的吸附特性,结果表明,溶液pH和温度对吸附率的影响较大,在磷酸根浓度为2 mg/L,pH=3,溶液温度为60℃时吸附率达到85.8%;吸附过程符合二级动力学吸附,符合Langmuir吸附模型,吸附为吸热、熵增、自发的过程。在7次吸附解吸循环试验中,相邻2次的吸附量变化不超过0.03 mg/g,说明多孔树脂具有良好的循环吸附稳定性。     

载药壳聚糖缓释微球的制备及其释放研究

实验采用乳化交联法,使用复合交联剂(先用甲醛交联,再用戊二醛交联),制得盐酸四环素壳聚糖缓释微球,并考察不同分子量的壳聚糖、原料质量比、交联剂用量、复合交联剂用量、搅拌速度对微球的影响,筛选出最佳条件制备出戢药微球,并研究了该微球在扫描电镜和倒置式研究型显微镜下的形态及其在pH=7.4,温度为37℃时的释放规律.结果表明,采用复合交联剂的乳化交联法所制得的微球球形好,粒径分布为5～50μm之间,载药量为26.9%,包封率为56.3%,并且具有良好的缓释效果.     

氧化微晶纤维素交联壳聚糖复合膜的制备及性能

目的 制备氧化微晶纤维素交联壳聚糖复合膜,并探索交联改性对壳聚糖复合薄膜性能的影响。方法 首先采用高碘酸钠氧化法对微晶纤维素进行氧化处理,制备氧化微晶纤维素,再通过溶液共混流延法制备不同质量分数(0%、1%、3%、5%、7%、9%)的氧化微晶纤维素交联壳聚糖复合薄膜。通过对复合薄膜组分、形貌、力学性能、光学性能、热稳定性及阻隔性能的表征,考察不同含量的氧化微晶纤维素对壳聚糖薄膜各性能的影响。结果 氧化微晶纤维素表面的醛基能与壳聚糖中的氨基发生交联反应,氧化微晶纤维素的加入可以改善壳聚糖薄膜的拉伸强度和断裂伸长率,复合薄膜的拉伸强度和断裂伸长率最大分别达到了43.07 MPa和19.42%;随着氧化微晶纤维素含量的增大,复合薄膜的紫外屏蔽性能增强,水蒸气透过系数增高,但热稳定性未见明显变化。结论 采用氧化微晶纤维素交联改性壳聚糖可以有效改善壳聚糖薄膜的力学性能和紫外屏蔽性能,有助于进一步扩大其包装应用范围。     

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.