Morphology and tribological properties of Ni/n-SiO_2 composite coatings by pulse-reverse current brush-plating

Ni/n-SiO2 composite coating was electrodeposited by brush-plating with pulse-reverse current（RC）. The morphology, hardness, and tribological properties of the coating were investigated and compared with those of Ni and composite coatings electrodeposited with direct current（DC）. The results indicate that Ni/n-SiO2 composite coating electrodeposited by RC, because of RC and the nano powders, has denser coating, finer crystal grains, higher hardness（HV650.0, nearly 1.5 times higher than that of Ni coating electrodeposited by DC） and lower friction coefficient（nearly 0.62）, as a result, in the wearing experiment, the Ni/n-SiO2 composite coating electrodeposited by RC has the least worn loss. So this kind of coating has better wear resistance. And RC electro brush-plating can be used as a new technology of brush-plating in the area of wear resistance.

Analysis on the Characteristic Properties of PEDOT Nano-particle Based on Reversed Micelle Method

Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,we deeply investigated the optical,electrical and the thermal stability of PEDOT nanoparticles.The main results are as follows： the small-sized PEDOT nanoparticles were prepared and utilized by different methods,such as ultraviolet/visible （UV-Vis） spectroscopy,Fourier-transform infrared （FT- IR） spectrum,scanning electron microscopy（SEM） and so on.The results show that the amount of oxidizer,ultrasonic treatment,polymerizing temperature and doping degree can influent morphology,electrical ability and gas sensitivity of PEDOT nanoparticles.The Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the better orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles than conventional PEDOT.

TWO DIMENSIONAL PROPERTIES OF REVERSED DUCKWEED AMPHIPHILIC POLYMER

The surface pressure-Area isotherms of Reversed Duckweed amphiphili polymer were examined in view of their chemical structure and two- dimentional properties of polymer monolayer were studied.

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

Catalytic Activity of Ceria-Zirconia Nanostructured Materials Prepared via Reversed Microemulsion Method

Single-phase homogeneous Ce1-x ZrxO2 solid versed microemulsion method. The structural properties solutions with various compositions were synthesized using the reand performance of Ce1- xZrxO2 were studied using XRD, BET, SEM, HRTEM, TPR and CO oxidation measurements. The results show that in the range of x = 0.4 - 0.5 and x = 0.6 - 1.0, the solid solutions posses the cubic and the tetragonal phase structure, respectively, Solids obtained by the reversed microemulsion method were more homogeneous on the whole range of composition, XRD investigations of the prepared materials did not show segregation of cerium or zirconium oxides, Highly uniform nanosize solid solution particles of ceria-zirconia with high specific area （146.7 m^2·g^-1） were attained under the conditions of this study. The TPR results and CO oxidation measurements indicate that the performance of the CeO2-ZrO2 mixed oxides is strongly related to the composition and structure of the oxides. Enhancement of the activity was found for the catalyst prepared by reversed microemulsion method as compared to the sample prepared by sol-gel method.

Generation of Recombinant Equine Influenza Vaccine Candidate RgH3N1 Virus by Reverse Genetics

The antigenic variation of influenza A virus hemagglutinin (HA) glycoproteins requires frequent changes in vaccine formulation. The new strategy of creating influenza seed strains for vaccine production is to generate 7 + 1 reassortants that contain seven genes from a high-yield virus A/Puerto Rico/8/34[A/PR/8/34](H1N1) and the HA gene from the circulating strains. By using this DNA-based cotransfection technique, we generated 7 + 1 reassortants rgH3N1 which had the antigenic determinants of influenza virus A/Songbird/HongKong/102/00[SB/HK/01](H3N8) and 7 other genes from A/PR/ 8/34. The hemagglutinin of A/Songbird/HongKong/102/00 is 96.3% homologous to that of A/Equine/Jilin/98[Eq/Jl/89] (H3N8). The resulting virus rgH3N1 grows to high HA titers in chicken embryonated eggs, allowing vaccine preparation in unconcentrated allantoic fluid. The rgH3N1 is stable after multiple passages in embryonated eggs. The reassortant rgH3N1 virus could be used as vaccine candidate to reduce the reemergence of equine influenza outbreaks.

Preparation and Characterization of Cathode Materials La_(0.7)Sr_(0.3-x)Ca_xCo_(0.9)Fe_(0.1)O_(3-δ) by Reverse Titration Co-Precipitation Method for ITSOFC

The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitation method with metal-nitrates as starting materials and mixed alkali (NaOH and Na2CO3) as a precipitating agent. The formation process of LSCCF from the precursors was monitored by TG-DSC, and the crystal structure and particles morphology of the precursors which were calcined at 600, 800, 1000 ℃ for 3 h were characterized using XRD, SEM technologies. Compared with the solid state reaction of constituent oxides, when the pH value of the precipitating solution was in the range of 9.1～9.5, the LSCCF powders from the precursors caclined at 800 ℃ for 3 h had high purity, homogeneous and single perovskite phase. The electrical conductivity of the LSCCF samples sintered at 1200 ℃ for 3 h, which was measured as a function of temperatures from 100 to 800 ℃ by DC four-probe method in air, decreased with x from 0.05 to 0.20. The value of electrical conductivity was almost equal because of Ca2+, Sr2+ co-dopant resulting in the 'mix effect' while x=0.10 or 0.15. The electrical conductivity of all doped samples was higher than 100 S·cm-1 at intermediate temperatures from 500 to 800 ℃, and there was good compatibility between the LSCCF cathode and Ce0.8Sm0.2O2 electrolyte.

Effects of dipolar interactions on magnetic properties of Co nanowire arrays

Magnetic properties and magnetization processes of Co nanowire arrays with various packing densities are investigated by means of object-oriented micromagnetic framework（OOMMF） software package with finite difference micromagnetic simulations. The packing density of nanowires is changed with the diameter, number of nanowires and center-to-center spacing between the wires. The magnetization reversal mechanism and squareness of the hysteresis loops of the nanowire arrays are very sensitive to the packing density of nanowires. Clear steps and plateaux on the demagnetization are visible,which turns out that dipolar interactions among the wires have a significant influence on switching field.

Syntheses,Crystal Structures and Properties of Two New Compounds from a Flexible Bipodal Acid with Additional Amide Groups

Two novel compounds {[Cu（IBG）（4,4-bipy）（H2O）2]2·11H2O}n（1） and {[Co（IBG）-（μ-H2O）（H2O）2]·2H2O}n（2） based on isophthaloylbisglycine（H2IBG） have been synthesized and structurally characterized by thermogravimetric analysis, elemental analysis and single-crystal X-ray diffraction. Compound 1 shows a 1D chain sine/cosine chain structure, and compound 2 can be characterized as a 4-connected sql tetragonal planar network with the point symbol of {44·62}. Compound 2 has been characterized by magnetic measurements. In addition, 1 and 2 display an interesting reversible crystal-to-amorphous transformation.

Statistical model of magnetization reversal in Nd-Fe-B sintered magnets

Statistical model of magnetization reversal was used to simulate the magnetization reversal behavior in the sintered Nd-Fe-B magnets with double grain-size distributions due to the abnormal grain growth (AGG). The magnetic properties and mechanical properties due to the formation of AGG grains in Nd-Fe-B sintered magnets were tested. The results show that the magnetic properties, especially the rectangularity were severely deteriorated after the formation of the AGG grains and a step was shown on the demagnetization curve, and the occurrence of AGG may account for the poor rectangularity and existence of the step on demagnetization curve according to the statistical model of magnetization reversal. The fracture toughness and bending strength are lowered because of the stress concentration in the AGG grains. The SEM images show that the formation of AGG grains is caused by the solid sintering due to the absence of RE-rich phase. Statistical model of magnetization reversal can qualitative by explain the dependence of the magnetization reversal behavior on the grain size in the Nd-Fe-B sintered magnets.

Increase of mechanical properties of hot plate due to introduction of a cycle of high-speed asymetry of work rolls on four-high mill 5000

In the given work results of researches asymmetric rolling on reversive mill 5000 are considered. By definition of boundary modes of asymmetry and an opportunity of application results of precomputations are resulted in production for various circuits of rolling. Results of influence of asymmetric rolling on physic and mechanical properties, structure and geometry hot sheets are shown, recommendations to introduction of modes of asymmetry in a production cycle of manufacturing of sheet-rolling production of the improved quality are

自修复聚氨酯材料的研究进展

聚氨酯材料因具有优异的综合性能而得到了广泛应用,但是其在使用过程中不可避免地会产生微裂纹等结构破坏,而自修复技术是解决这一问题的有效方案。本文阐述了非本征型和本征型自修复的机理,重点综述了本征型自修复材料的设计方法和研究进展,讨论了不同设计方法对材料自修复性能、力学性能等的影响,最后针对自修复材料自修复性能和力学性能的平衡问题,探讨了复合型自修复体系的可行性、设计思路和最新进展,提出了复合型自修复材料是今后的一大发展趋势,并展望了自修复材料面临的挑战和发展方向。

水飞蓟蛋白提取工艺优化及理化性质

目的优化反胶束法萃取水飞蓟蛋白工艺,探究该方法对水飞蓟蛋白理化性质的影响。方法通过单因素试验和响应面试验优化反胶束法萃取水飞蓟蛋白工艺,分析提取因素对蛋白提取率的影响;对比碱提酸沉法,分析反胶束法水飞蓟蛋白溶解度、持油性、起泡性、起泡稳定性、乳化性及乳化稳定性。结果反胶束法萃取水飞蓟蛋白最佳提取工艺参数为含水量20、液固比201(mL g)、前萃取pH 8.0、前萃取温度40℃、后萃取时间90 m in、后萃取pH 8.0,该条件下水飞蓟蛋白提取率为(60.44±0.20)%;反胶束法萃取的水飞蓟蛋白溶解度、持油性、起泡性、乳化性和乳化稳定性均高于碱提酸沉法提取的水飞蓟蛋白。结论反胶束法提取水飞蓟蛋白较传统方法更具优势,在水飞蓟蛋白开发中具有较好的应用前景。

反向处理铜箔微纳组织形成机理及其对力学性能的作用机制

目的第五代移动通信技术(5G)时代,高频高速信号传输过程中由于“趋肤效应”引起的信号损耗甚至“失真”越来越严重,为了解决这一问题,提出了一种反向处理铜箔的新技术,然而国内当前应用的高性能反向处理铜箔(RTF)主要依赖进口,要想在短时间内缩小国内外铜箔性能和生产效率的差距,最终实现这类高端铜箔的国产化,必须在明确该类铜箔微纳结构形成机理及其对性能影响的前提下,加快制备工艺的开发和优化。方法采用电镀法在阴极钛辊上沉积了电解生箔,在其光面进行粗化和镀Zn层等后续处理获得反向处理铜箔,同时以国外反向处理铜箔为参照,采用X射线衍射仪、扫描电子显微镜和透射电子显微镜详细分析其微纳组织与结构,采用激光共聚焦显微镜和万能试验机测量其粗糙度和拉伸性能。结果本工作中的RTF具有与国外商业产品相似的微观结构,由小的等轴晶和较大的柱状晶组成,且包含较多的纳米孪晶,孪晶界占比为30.8%,平均宽度为7.9 nm。S面是均匀的米粒状铜颗粒,而M面是较大的圆锥形铜颗粒。S面上的Zn层均匀致密,厚度约为6.5 nm,只有小部分Zn扩散到基底上形成CuZn3相。但从S面到M面,优选取向从(111)Cu逐渐变为(220)Cu,这与参比RTF略有不同。性能方面,参比RTF的Ra和Rz分别为1.22、1.42μm,抗拉强度为335.10 MPa,伸长率为15.5%,本工作中的RTF具有较低的粗糙度,Ra和Rz分别为0.68、1.03μm,其强度也具有明显优势(393.68 MPa),但延展性低于参比样品。通过对比分析,总结了铜箔在初始外延、过渡生长和电沉积条件控制的生长阶段3个阶段的生长特性,给出了影响每个阶段晶粒生长的主要因素,并且详细讨论了晶粒尺寸和纳米孪晶宽度对铜箔拉伸性能的影响。结论对RTF微观结构和性能的深入研究,有助于找到高性能铜箔国产化“瓶颈”的根源,为高性能铜箔在5G通信领域的进一步发展和应用奠定基础。

疏水改性微球的制备及其膨胀性能与应用研究

通过反相乳液聚合法制备了一种疏水改性P(AM-N)微球.采用傅里叶变换红外光谱(FTIR)、热重分析仪(TGA)、扫描电镜(SEM)、流变及岩心驱替实验对所合成微球的结构、形貌、性能以及封堵效果进行了表征与测试,并考察了溶胀时长、温度和不同盐溶液浓度对P(AM-N)微球性能的影响.测试结果表明,P(AM-N)微球的平均粒径为76.42 nm,溶胀5 d后P(AM-N)微球的膨胀率高达17.21倍;在70℃下,P(AM-N)微球老化2 d后溶胀率高达17.14倍,在20000 mg/L NaCl溶液和2000 mg/L CaCl_(2)溶液中分别溶胀3 d后膨胀率高达5.31倍和6.03倍,说明其具有较好的耐温性和抗盐性;在注入量为0.5%的条件下,P(AM-N)微球封堵率可达到97.98%,与P(AM)微球相比具有更好的封堵性且弹性增强.

自修复与阻燃功能一体化玄武岩纤维增强环氧树脂基复合材料的制备及性能

纤维增强环氧树脂基复合材料(FREPC)在实际应用中常因裂纹失效和燃烧破坏而受到限制。文中将自制的DA加合物(DOPO-FU-BMI)与糠胺(FA)配合,引入到环氧树脂DGEBA中,通过热压成型工艺制备了兼具自修复和阻燃双重功能的玄武岩纤维增强环氧树脂基复合材料。结果表明,DA加合物在复合材料中实现了均匀分布,提升了材料的热稳定性和玻璃化转变温度;复合材料通过动态可逆化学键的可逆Diels-Alder(DA)反应实现了裂纹的修复,当DA加合物质量分数为20%时,经2次“冲击-修复”循环后复合材料的强度保留率仍高达92.5%;同时,复合材料发挥了玄武岩纤维的阻燃特性优势,引入DA加合物后使其阻燃性能进一步增强,极限氧指数最高可达44.5%,较未改性复合材料提升25.4%。

双(2-柠康酰亚胺苯基)二硫化物对天然橡胶性能的影响

采用双(2-柠康酰亚胺苯基)二硫化物(BCoPD)作为天然橡胶(NR)的多功能硫化助剂,通过机械共混制备BCoPD/NR复合材料,探讨BCoPD用量和复合材料制备方法对BCoPD/NR复合材料的门尼粘度、Payne效应、硫化特性、交联键分布、物理性能和动态力学性能的影响。结果表明:采用在生胶塑解过程中加入BCoPD的BCoPD/NR复合材料制备方法,加入0.5份BCoPD使得复合材料的门尼粘度下降22.2%,60 min时的抗硫化返原率减小3%,多硫键比例增大3%,物理性能小幅下降,抗湿滑性能小幅提高;采用在加硫化体系时加入BCoPD的BCoPD/NR复合材料制备方法,加入1份BCoPD使得复合材料60 min时的抗硫化返原率下降11.9%,多硫键比例增大4%,物理性能有所提高,滚动阻力小幅下降。

铝源对Cu-Al尖晶石物化性质和逆水煤气变换性能的影响

基于高能球磨和固相焙烧的方法,采用杂质元素(Na、Fe、Si和S)含量不等的四种拟薄水铝石和氢氧化铜制备了Cu-Al尖晶石固溶体催化剂,通过ICP-AES、TG、XRD、H2-TPR和BET表征了催化剂的物化性质,并考察了对逆水煤气变换反应的催化性能。结果表明,拟薄水铝石中的杂质元素对于Cu-Al尖晶石催化剂的物相性质、还原性能、织构性质和催化性能有显著的影响,Si有助于合成高比表面积的催化剂,但不利于Cu-Al尖晶石生成,导致催化活性低;含有少量Na和Fe的尖晶石的催化活性较低;S物种经高温焙烧后分解,对催化活性没有影响;基于杂质元素含量最低的拟薄水铝石合成的催化剂中难还原尖晶石含量最高,表现出最高的逆水煤气变换催化活性。此外,基于活性最优样品的CO_(2)-TPDMS和In-situ DRIFTS分析表明,Al上形成的双齿甲酸盐是Cu-Al尖晶石固溶体催化CO_(2)加氢生成CO的主要中间产物,其含量与催化活性随反应时间的变化规律一致。

基于表面印迹技术的双酚A磁性分子印迹聚合物的制备、表征及应用

目的制备双酚A(bisphenol A,BPA)磁性分子印迹聚合物(magnetic molecularly imprinted polymer,MMIPs)并研究其吸附性能和在奶粉检测中的应用。方法以双酚A为模板分子,以3-氨丙基三乙氧基硅烷(3-aminopropyl triethoxysilane,APTES)为功能单体,采用反向微乳法和表面印迹技术制备了核壳型SiO2包裹Fe3O4磁性分子印迹聚合物(Fe3O4@SiO2 MMIPs),并对其进行透射电镜、扫描电镜、傅里叶变换红外光谱、X射线衍射、热重分析和振动样品磁强计表征,并研究Fe3O4@SiO2 MMIPs的吸附性能和在奶粉检测中的应用。结果制备出的双酚A磁性分子印迹聚合物选择性好,吸附性能好,结合高效液相色谱法,成功应用于奶粉中双酚A的检测。双酚A在5~200μg/kg范围内呈现良好的线性关系,定量限为1.67μg/kg,回收率为89.9%~92.3%,日内、日间精密度均小于4.0%。结论Fe3O4@SiO2 MMIPs是一种较好的双酚A富集材料,可用于奶粉中双酚A检测的前处理工艺。

捻系数比对针织用棉汉麻混纺股线性能的影响

为探究棉汉麻混纺纱合股时捻系数比对股线性能的影响,将棉/汉麻65/3518.4 tex集聚纱以不同的捻系数比反向加捻为股线,对股线的强力、毛羽、条干、耐磨性能等进行测试,并对试验测试结果进行模糊综合评价。试验结果表明:当捻系数比在0.52~0.95时,随着捻系数比的增大,股线的断裂强力和断裂伸长率先减小后增大,3 mm毛羽数先增大后减小,耐磨性能逐渐提高;当捻系数比超过0.95后,3 mm毛羽数又开始增长,断裂伸长率逐渐减小。当捻系数比为0.95时,棉汉麻混纺股线的综合性能表现最好,考虑针织物织造需求和风格要求,可选择捻系数比在0.90~0.95的棉汉麻混纺股线。