In vitro and in vivo evaluations of Mg-Zn-Gd alloy membrane on guided bone regeneration for rabbit calvarial defect

To develop a biodegradable membrane with guided bone regeneration(GBR),a Mg-2.0Zn-1.0Gd alloy(wt.%,MZG)membrane with Ca-P coating was designed and fabricated in this study.The microstructure,hydrophilicity,in vitro degradation,cytotoxicity,antibacterial effect and in vivo regenerative performance for the membrane with and without Ca-P coating were evaluated.After coating,the membrane exhibited an enhance hydrophilicity and corrosion resistance,showed good in vitro cytocompatibility upon MC3T3E-1 cells,and exhibited excellent antibacterial effect against E.coli,Staphylococcus epidermis and Staphylococcus aureus,simultaneously.In vivo experiment using the rabbit calvarial defect model confirmed that Ca-P coated MZG membrane underwent progressive degradation without inflammatory reaction and significantly improved the new bone formation at both 1.5 and 3 months after the surgery.All the results strongly indicate that MZG with Ca-P coating have great potential for clinical application as GBR membranes.

Progress of Palladium Alloy Membranes in Hydrogen Energy

Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability, perm -selectivity and thermal stability. This paper review the principle of hydrogen permeation, type of alloys and the fabrication methods. At last, the progress and achievements on palladium alloy membranes by Northwest Institute for Non-Ferrous Metal Research are emphasized.

Preparation Methods and Properties of PdCu Alloy Membrane for Hydrogen Transition

Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.

Analysis of H_2S Tolerance of Pd-Cu Alloy Hydrogen Separation Membranes

The presence of a limited amount of H2S in H2-rich feed adversely affects the Pd-Cu membrane permeation performance due to the sulphidization of the membrane surface. A theoretical model was proposed to predict the S-tolerant performance of the Pd-Cu membranes in presence of H2S under the industrial water-gas-shift(WGS) reaction conditions. The ideas of surface coverage and competitive adsorption thermodynamics of H2S and H2 on Pd-Cu surface were introduced in the model. The surface sulphidization of the Pd-Cu membranes mainly depended on the pressure ratio of H2S to H2, temperature and S-adsorbed surface coverage, i.e., the occurrence of sulphidization on the surface was not directly related with the bulk compositions and structures [body centered cubic and face centered cubic(bcc or fcc)] of Pd-Cu alloy membranes because of the surface segregation phenomena. The resulting equilibrium equations for the H2S adsorption/sulphidization reactions were solved to calculate the pressure ratio of H2S to H2 over a wide range of temperatures. A validation of the model was performed through a comparison between lots of literature data and the model calculations over a rather broad range of operating conditions. An extremely good agreement was obtained in the different cases, and thus, the model can serve to guide the development of S-resistant Pd alloy membrane materials for hydrogen separation.

Electrochemical Study of Lincomycin on Au-PtNPs/nanoPAN/ Chitosan Nanocomposite Membrane and Its Determination in Injections

The Au-Pt alloy nanoparticles（Au-PtNPs） were electrochemically deposited on the surface of polyaniline nanotube（nanoPAN） and chitosan（CS） modified glassy carbon electrode（GCE）. The electrochemical behavior of lincomycin at Au-PtNPs/nanoPAN/CS modified GCE was investigated by cyclic voltammetry, linear sweep voltammetry and chronocoulometry. Cyclic voltammetric experiments show that lincomycin at the nanocomposite membrane modified electrode exhibited a pair of quasi-reversible redox peaks in pH=6.0 PBS. The membrane could accelerate the electron transfer of lincomycin on the electrode and significantly enhance the peak current. In a range of 3.0-100.0 mg/L, the reductive peak current of lincomycin at 0.42 V was linearly related to its concentration and the linear regression equation was ip,c=0.2703ρ-0.0042（ip, c： μA; ρ： mg/L; r=0.998, n=7） with a detection limit of 1.0 mg/L（S/N =3）. Compared with other methods, this method exhibited many advantages such as high sensitivity, selectivity, wide linear range and low detection limit. The method was used to determine the content of lincomycin in injections commercially available with satisfactory results. Some electrochemical parameters involved in the redox reaction of lincomycin, such as parameter of kinetic ha, standard rate constant ks and the number of H^＋, were also calculated.

Large-scale and high-quality III-nitride membranes through microcavity-assisted crack propagation by engineering tensile-stressed Ni layers

Epitaxially grown III-nitride alloys are tightly bonded materials with mixed covalent-ionic bonds.This tight bonding presents tremendous challenges in developing III-nitride membranes,even though semiconductor membranes can provide numerous advantages by removing thick,inflexible,and costly substrates.Herein,cavities with various sizes were introduced by overgrowing target layers,such as undoped GaN and green LEDs,on nanoporous templates prepared by electrochemical etching of n-type GaN.The large primary interfacial toughness was effectively reduced according to the design of the cavity density,and the overgrown target layers were then conveniently exfoliated by engineering tensile-stressed Ni layers.The resulting III-nitride membranes maintained high crystal quality even after exfoliation due to the use of GaN-based nanoporous templates with the same lattice constant.The microcavity-assisted crack propagation process developed for the current III-nitride membranes forms a universal process for developing various kinds of large-scale and high-quality semiconductor membranes.

Palladium-based Membrane Applications for Hydrogen Purification

It describes the purification of hydrogen isotopes, separation with the preparation of palladium-based membrane's technology, types, application, advantages and disadvantages of palladium in this article. Due to excellent comprehensive properties palladium composite membrane will become the future direction of development. At the same time it will develop preparation methods of the membrane support body with high mechanical strength and heat resistance and low-cost and palladium-based membrane. Also it will explore high service life and high transmittance of novel composite membrane.

Fabrication of anodized aluminum oxide membrane with nanometer pores

The pure aluminum and Al Mg Mn alloy were anodized in 4%, 10% and 18.5% phosphoric acid solution, respectively. As for pure Al, the maximum thickness of anodized aluminum oxide (AAO) membrane, 216 nm, is obtained by being anodized in 4% solution. Its average pore diameter is around 70 nm, and pore density exceeds 10 10 /cm 2. Under the same technology condition, the membrane thickness decreases with increment of electrolyte content. TEM images show that element Mg or Mn added into aluminum alloy can damage the integration of AAO membrane. During anodizing of aluminum, the formed oxide layer is amorphous. After being annealed at 600 ℃ for 24 h, it is still amorphous. However, when membrane is annealed at 930 ℃, the amorphous oxide begins to transform to γ Al 2O 3 .

High-loading Pt-alloy catalysts for boosted oxygen reduction reaction performance

To improve performance of membrane electrode assembly(MEA)at large current density region,efficient mass transfer at the cathode is desired,for which a feasible strategy is to lower catalyst layer thickness by constructing high loading Pt-alloy catalysts on carbon.But the high loading may induce unwanted par-ticle aggregation.In this work,H-PtNi/C with 33%(mass)Pt loading on carbon and monodisperse distri-bution of 3.55 nm PtNi nanoparticles,was prepared by a bimodal-pore route.In electrocatalytic oxygen reduction reaction(ORR),H-PtNi/C displays an activity inferior to the low Pt loading catalyst L-PtNi/C(13.3%(mass))in the half-cell.While in H_(2)-0_(2) MEA,H-PtNi/C delivers the peak power density of 1.51 W·cm^(-2) and the mass transfer limiting current density of 4.4 A·cm^(-2),being 21%and 16%higher than those of L-PtNi/C(1.25 W·cm^(-2),3.8 A·cm^(-2))respectively,which can be ascribed to enhanced mass trans-fer brought by the thinner catalyst layer in the former.In addition,the same method can be used to pre-pare PtFe alloy catalyst with a high-Pt loading of 36%(mass).This work may lead to a range of catalyst materials for the large current density applications,such as fuel cell vehicles.

Nickel boride alloys as catalysts for successive hydrogen generation from sodium borohydride solution

Nickel boride alloys,Ni-B,were prepared using chemical reduction method by the reaction of metal chloride with sodium borohydride,and heat-treated at various temperatures. The structures of the as-prepared alloys were studied using X-ray diffractometry(XRD),scanning electronic microscopy(SEM) and nitrogen adsorption-desorption analysis. When being adopted as the catalysts for successive hydrogen generation from sodium borohydride solution,the Ni-B alloy treated at 90 ℃ achieves a maximum hydrogen generation rate of 15.4 L/(min·g),and an average hydrogen generation rate of 13.6 L/min,which can give successive hydrogen supply to a 2.2 kW PEMFC at a hydrogen utilization of 100%.

PtIr双功能催化剂膜电极制备及抗反极性能研究

燃料供应不足会导致质子交换膜燃料电池膜电极电压反转,造成阳极催化层中的碳载体发生严重腐蚀,进而给燃料电池带来不可逆的损伤。为了解决该问题,采用双功能PtIr合金作为阳极催化剂制备膜电极,并对其进行了电极极化性能、反极和交流阻抗等测试。结果表明,PtIr/C电极的峰值功率密度可达1.49 W/cm^(2),较Pt/C-IrO_(2)(50%)电极(1.46 W/cm^(2))提高2.1%。反极结果表明,PtIr/C电极抗反极时间725 s,较掺杂IrO_(2)的Pt/C电极反极性能略差,但在整个反极过程中PtIr/C电极呈现出更低的绝对反转电压,以及反极后保持更高的结构稳定性。反极后PtIr/C电极峰值功率密度降为1.18 W/cm^(2),衰减约20.80%,而Pt/C-IrO_(2)(50%)电极的峰值功率密度降至1.09 W/cm^(2),衰减约25.34%。PtIr/C电极相较掺杂IrO_(2)的Pt/C电极具有更佳的初始极化性能和优异的抗反极能力。该研究结果对质子交换膜燃料电池高性能长寿命膜电极催化层设计具有重要的意义。

Study on repairing canine mandibular defect with porous Mg-Sr alloy combined with Mg-Sr alloy membrane

To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted from six dogs.The model of mandible buccal fenestration bone defects were prepared after the sockets healed.Twelve bone defects were randomly divided into groups A and B,then Mg-Sr alloy was implanted in bone defects of group A and covered by Mg-Sr alloy membrane while Mg-Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane.Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4,8 and 12 weeks.After 12 weeks,the healing of bone defects were evaluated by gross observation,X-ray microscopes and histological observation of hard tissue.Bone defects in each group were repaired.At 8 and 12 weeks,the gray value of group A was higher than that of group B(P<0.05).At 12 weeks,the bone volume fraction of group A was higher than that of group B(P<0.05).The newly woven bone in group A is thick and arranged staggered,which was better than that of group B.Porous Mg-Sr alloy combined with Mg-Sr alloy membrane could further promote the repair of mandibular defects,and obtain good osteogenic effect.

氮气流量对VNbMoTaWN_(x)薄膜作为PEMFC不锈钢双极板改性层性能的影响

目的降低SS316L表面的接触电阻,提高耐腐蚀性能。方法采用非平衡场磁控溅射离子镀技术在SS316L不锈钢表面制备VNbMoTaW和不同氮气流量的VNbMoTaWN_(x)薄膜。使用场发射扫描电镜、XRD衍射仪、XPS光电子能谱仪、电化学工作站、接触电阻测试装置,研究了改性涂层的组成和结构对接触电阻和耐腐蚀性能的影响。结果扫描电子显微镜结果表明,所有薄膜表面致密且连续、与基体结合良好。随着氮气流量的增加,氮化物相逐渐增多、柱状晶结构减少、薄膜更加致密紧凑。XRD结果表明,未通氮气的高熵合金薄膜具有高熵合金体心立方结构,并沿(110)晶面方向生长。随着氮气流量的增加,氮化物相逐渐增多,薄膜晶体结构开始从体心立方结构转变为面心立方结构。结合XPS分析结果可知,VNbMoTaWN_(x)薄膜表面主要由金属氮化物和少量高熵合金BCC相组成,并且随着氮气流量的增加,金属氮化物相逐渐增多。与单层VNbMoTaW薄膜相比,VNbMoTaWN_(x)薄膜具有更好的耐腐蚀性和导电性能。氮流量为12mL/min的高熵合金氮化物薄膜具有最优异的综合性能。表面改性后的薄膜接触电阻大幅度降低,在1.4MPa的压力下,与碳纸的接触电阻仅为12.2 mΩ·cm^(2),接近美国能源部(DOE)的技术目标。由动电位极化曲线测得VNbMoTaWN_(x)-12mL/min在模拟PEMFC阴极环境下的腐蚀电流密度为0.040μA/cm^(2),与SS316L基体相比,薄膜的耐腐蚀性得到了很大提升。在0.6 V恒电位模拟阴极环境下,VNbMoTaWN_(x)-12 mL/min的电流密度稳定在1.01μA/cm^(2),接近美国能源部1μA/cm^(2)的目标。结论VNbMoTaW和不同氮气流量的VNbMoTaWN_(x)薄膜能显著提高SS316L基体的耐腐蚀性和导电性能。

ETFE膜在怀柔科学城城市客厅A地块项目中的应用

ETFE膜因其良好的透视和遮阳功能,能够有效避免阳光照射进玻璃幕墙而导致的室内温度过高,但其施工经验尚有不足。研究结合怀柔科学城城市客厅A地块项目,充分考虑了施工技术和施工组织管理的重难点,详细介绍了ETFE膜的施工全过程,保证了施工质量,丰富了施工经验。

Preparation and Characterization of Ultra-thin Pd-Ag Alloy Membranes

Ultra-thin Pd-Ag alloy membranes were prepared initially by cold rolling, and it was found that there exist a large number of defects such as pinholes or cracks in the as-rolled membranes. Subsequently, these defects were repaired using electroless plating technique. The morphologies of the membranes have been examined by scanning electron microscopy （SEM）. It was observed in some as-repaired membranes that the defects were disappeared. A hydrogen permeation study has demonstrated that the as-repaired Pd-Ag alloy membranes were of high hydrogen permeation flux and hydrogen selectivity.

PEMFC铝合金双极板表面改性研究现状与发展

质子交换膜燃料电池(Proton Exchange Membrane Fuel Cell,PEMFC)作为第五代燃料电池,是最具发展前景的新能源电池,其中双极板作为PEMFC的核心元件,不仅能将单一电池链接起来形成电池堆,起到支撑作用,还具有提供气体流道、隔绝阴阳极两端等作用,对燃料电池工作性能、寿命起到关键作用。其中铝合金作为一种具有良好导电性能、成本低、轻质的材料,在PEMFC双极板材料方面应用潜力巨大。但铝合金双极板耐腐性不佳,在PEMFC工作环境下极易被腐蚀,且其表面生成的钝化膜,增大了电池的接触电阻,从而对电池性能和寿命产生不利影响,而通过铝合金表面改性是解决该问题的主流方法。首先概述了PEMFC原理、双极板材料类型及内部环境,然后阐述了PEMFC中铝合金双极板的服役问题,并对近年来铝合金双极板的表面改性进行分类。重点概括了铝合金表面金属及其化合物涂层(贵金属、金属氮/碳化物、镍磷金属涂层)与非金属涂层(碳基涂层、高分子聚合物涂层)的结构设计、成分优化、服役性能特点。分析结果表明,选用低成本、具有良好耐蚀性和导电性的金属惨杂的无定型碳、金属碳/氮化物涂层,能降低双极板生产成本,提高双极板工作性能,并对涂层设计出多层复合涂层,能打断涂层中的细长针孔缺陷,提高涂层的完整性和致密性。在铝合金表面进行改性研究,以提高其耐蚀性、导电性及服役稳定性,对推动铝合金双极板在PEMFC电堆中的应用至关重要。

Microstructural development of vanadium-nickel crystalline alloy membranes

V85Ni15(at%)alloy was proposed as a promising candidate for hydrogen separation membranes.To date,investigations of V85Ni15 alloy have concentrated on hydrogen permeation characteristics,and little work has been done on the microstructural development.In the present study,various fabrication and heat-treatment techniques were used to develop different microstructures which would then be tailored to achieve a desired candidate for acceptable mechanical stability while maintaining high hydrogen permeability.The arc-melted(AM)V85Ni15 alloy are supersaturated solid solution with dendritic segregation of Ni-solute atoms.Cold rolling(CR)followed by annealing at 1050℃and 850℃can produce a two-phase(V+σ)microstructure and a three-phase(V+σ+NiV3)microstructure,respectively.Very fine two-phase microstructure obtained at 1050℃involves a simultaneous reaction of second-phase precipitation and V-matrix recrystallization.Sigma phase is formed via primary precipitation,while NiV3 phase is formed by peritectoidal reaction.When AMCR samples were homogenized at1250℃for 2 h and sequential heat-treated at 850℃or900℃for 2 h,precipitation-strengthening microstructure is obtained:large grain structure of V-matrix with uniform distribution of second-phase particles produced by recrystallization and grain growth followed by precipitation process.

透氢钯复合膜的原理、制备及表征

钯及其合金膜由于具有透氢性好和耐高温的特点,除了用作氢气分离和纯化器外,还可以用作脱氢、制氢等反应的反应器,以实现反应和分离的一体化,并提高转化率和选择性。本文综述了钯基复合膜的原理、制备及表征,并重点介绍了本研究组的光催化镀膜工艺。

国外氢分离及净化用钯膜的研究进展

介绍了氢分离及净化用钯膜的氢选择性机理、影响因素以及制备技术的进展情况,重点阐述了钯合金(如Pd-Cu,Pd-V,Pd-V-Cu,Pd-V-Ni-Co等)以及钯复合膜(如多孔不锈钢、Ni、Fe-Al-Cr基体等)的一些新的研究成果。

Mg元素对铝合金微弧氧化陶瓷膜的影响

选择磷酸盐为主要成分的复合电解液体系,用微弧氧化方法对3种常用的商业铝合金物陶瓷膜分别用扫描电镜、能谱仪、X射线衍射等探讨了铝合金中元素Mg对陶瓷层的组织形貌、元素分布和相组成的调制作用,并借助硬度、摩擦磨损测试评价了膜层的性能。结果表明膜的相结构主要为γ-Al2O3,α-Al2O3和AlPO4,并含有少量Mg、Cu、Zn、W元素;随着Mg含量的增加表面组织更加细密,膜层中大尺寸缺陷减少;膜层中α-Al2O3含量随Mg含量的增加逐渐减少,当Mg含量接近2.5%时,膜层中只剩下γ-Al2O3;硬度与摩擦磨损测试显示Mg含量的增加导致硬度和耐磨性能下降。