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981.
X‐Ray Spectroscopic Investigation of Chlorinated Graphene: Surface Structure and Electronic Effects 下载免费PDF全文
Xu Zhang Theanne Schiros Dennis Nordlund Yong Cheol Shin Jing Kong Mildred Dresselhaus Tomás Palacios 《Advanced functional materials》2015,25(26):4163-4169
Chemical doping of graphene represents a powerful means of tailoring its electronic properties. Synchrotron‐based X‐ray spectroscopy offers an effective route to investigate the surface electronic and chemical states of functionalizing dopants. In this work, a suite of X‐ray techniques is used, including near edge X‐ray absorption fine structure spectroscopy, X‐ray photoemission spectroscopy, and photoemission threshold measurements, to systematically study plasma‐based chlorinated graphene on different substrates, with special focus on its dopant concentration, surface binding energy, bonding configuration, and work function shift. Detailed spectroscopic evidence of C–Cl bond formation at the surface of single layer graphene and correlation of the magnitude of p‐type doping with the surface coverage of adsorbed chlorine is demonstrated for the first time. It is shown that the chlorination process is a highly nonintrusive doping technology, which can effectively produce strongly p‐doped graphene with the 2D nature and long‐range periodicity of the electronic structure of graphene intact. The measurements also reveal that the interaction between graphene and chlorine atoms shows strong substrate effects in terms of both surface coverage and work function shift. 相似文献
982.
Blake N. Johnson Karen Z. Lancaster Gehua Zhen Junyun He Maneesh K. Gupta Yong Lin Kong Esteban A. Engel Kellin D. Krick Alex Ju Fanben Meng Lynn W. Enquist Xiaofeng Jia Michael C. McAlpine 《Advanced functional materials》2015,25(39):6205-6217
A 3D printing methodology for the design, optimization, and fabrication of a custom nerve repair technology for the regeneration of complex peripheral nerve injuries containing bifurcating sensory and motor nerve pathways is introduced. The custom scaffolds are deterministically fabricated via a microextrusion printing principle using 3D models, which are reverse engineered from patient anatomies by 3D scanning. The bifurcating pathways are augmented with 3D printed biomimetic physical cues (microgrooves) and path‐specific biochemical cues (spatially controlled multicomponent gradients). In vitro studies reveal that 3D printed physical and biochemical cues provide axonal guidance and chemotractant/chemokinetic functionality. In vivo studies examining the regeneration of bifurcated injuries across a 10 mm complex nerve gap in rats showed that the 3D printed scaffolds achieved successful regeneration of complex nerve injuries, resulting in enhanced functional return of the regenerated nerve. This approach suggests the potential of 3D printing toward advancing tissue regeneration in terms of: (1) the customization of scaffold geometries to match inherent tissue anatomies; (2) the integration of biomanufacturing approaches with computational modeling for design, analysis, and optimization; and (3) the enhancement of device properties with spatially controlled physical and biochemical functionalities, all enabled by the same 3D printing process. 相似文献
983.
Fan Hui-li Ran Fen Zhang Xuan-xuan Song Hai-ming Niu Xiao-qin Kong Ling-bin Kang Long 《纳微快报(英文)》2015,7(1):59-67
Nano-Micro Letters - This article reported the electrochemical behaviors of a novel hollow carbon microspheres/manganese dioxide nanosheets (micro-HC/nano-MnO2) composite prepared by an in situ... 相似文献
984.
介绍了在国外同类变速器产品的基础上开发设计的6D79六挡变速器,该产品是在消化和吸收国外同类变速器产品的优点和特长后经过一系列改进、创新而研发出来的新型六挡变速器,详细阐述了操纵机构和回转机构设计的原理和特点。 相似文献
985.
Jianliang Li Dangsheng Xiong Yongkang Zhang Heguo Zhu Yongkun Qin Jian Kong 《Tribology Letters》2011,43(2):221-228
The solid lubricant that is coated on a flat surface is easily removed during friction. Surface texture dimples, which act
as reservoirs of solid lubricant, can prolong the wear life of solid lubricant films. We textured silver-containing nickel-based
alloys by a pulse laser and filled the micro-dimples with molybdenum disulfide powders. The tribological properties of the
alloys were tested by rubbing against alloyed steel on a ring-on-disk tribometer at temperatures ranging from room temperature
to 600°C . After laser surface texturing, the friction coefficients of the silver-containing nickel-based alloy smeared with
molybdenum disulfide powders were reduced at temperatures ranging from room temperature to 400°C. With increasing dimple density,
the wear life of the MoS2 film increased while the wear rate of the nickel-based alloy decreased. The wear life of the textured surface with a dimple
density of 11.2% exceeded 10,000 m at room temperature. We conclude that molybdenum disulfide and its oxides stored in the
micro-dimples play a role in lubrication at room temperature and high temperatures, respectively. 相似文献
986.
采用包套锻造技术成功制备Ti-45Al-5.4V-3.6Nb-0.3Y合金锻饼,并研究热处理对该合金锻饼组织和性能的影响。通过热处理得到3种不同的组织形态,分别为双态、近层片、和全层片组织,分析热处理过程中合金组织的演变规律,并对不同组织形态的合金进行力学性能测试。结果发现,双态组织的合金具有最好的室温塑性,其值可达1.35%,近层片组织的合金具有较高的室温强度,屈服强度为605.31MPa,断裂强度为665.75MPa。 相似文献
987.
系统地研究了La0.65Mg0.35Nix(x=3.0~3.5)储氢合金电极的自放电性能。结果表明,随着Ni含量的增加,合金电极最大放电容量从350.6mAh·g-1(x=3.0)增加到351.2mAh·g-1(x=3.1),然后减小到244.1mAh·g-1(x=3.5)。72h自放电的容量保持率从77.7%(x=3.0)增加到79.5%(x=3.1),然后又降低到63.5%(x=3.5)。说明适中的Ni含量有利于降低合金电极的自放电率。通过测量合金电极的P-C-T曲线和合金的腐蚀曲线分析了合金电极自放电性能的变化规律。 相似文献
988.
AgO超细粉末的制备及银的价态变化研究 总被引:1,自引:0,他引:1
采用臭氧氧化硝酸银制备了高纯AgO超细粉末,利用差热法研究了AgO在不同温度下银的价态变化,同时采用X射线衍射、扫描电子显微镜和X射线光电子能谱等方法,分析了AgO粉末的物相、形貌以及不同温度加热后粉末中银的价态变化。结果表明,制备的AgO超细粉末属于单斜晶系,AgO粉末呈棒状。AgO超细粉末经过加热后,其颜色发生明显变化,且随着加热温度升高,粉末中AgO含量逐渐减少,Ag2O含量先增加后减少,Ag含量逐渐增加。当温度高于350℃时,AgO全部分解,46.49%转化为Ag2O,53.51%转化为Ag,至400℃时全部分解成银。XPS高分辨结果表明,不同粉末中氧的结构明显不同,反映出粉末中相的变化。 相似文献
989.
Modelling and simulation of structure surface generation using computer controlled ultra-precision polishing 总被引:1,自引:0,他引:1
The applications of structured surfaces have been more widespread. However, research on the fabrication of these surfaces is still far from complete. The paper presents a theoretical and experimental investigation of the generation of structured surfaces by using Computer Controlled Ultra-precision Polishing (CCUP). A surface topography simulation model and hence a model-based simulation system for the modelling and simulation of the generation of structure surfaces by using CCUP have been established and verified through a series of simulation and practical polishing experiments. The results of experiments demonstrate the capability of the model-based simulation system in predicting the form error and the pattern of the 3D-texture generated by using CCUP. 相似文献
990.
Sun Ja Kim Jaeyoung Lee Kyung Yong Kong Chang Ryul Jung In-Gyu Min Sang-Yeop Lee Hyoung-Juhn Kim Suk Woo Nam Tae-Hoon Lim 《Journal of power sources》2007,170(2):412-418
Sodium borohydride (NaBH4) in the presence of sodium hydroxide as a stabilizer is a hydrogen generation source with high hydrogen storage efficiency and stability. It generates hydrogen by self-hydrolysis in aqueous solution. In this work, a Co–B catalyst is prepared on a porous nickel foam support and a system is assembled that can uniformly supply hydrogen at >6.5 L min−1 for 120 min for driving 400-W polymer electrolyte membrane fuel cells (PEMFCs). For optimization of the system, several experimental conditions were changed and their effect investigated. If the concentration of NaBH4 in aqueous solution is increased, the hydrogen generation rate increases, but a high concentration of NaBH4 causes the hydrogen generation rate to decrease because of increased solution viscosity. The hydrogen generation rate is also enhanced when the flow rate of the solution is increased. An integrated system is used to supply hydrogen to a PEMFCs stack, and about 465 W power is produced at a constant loading of 30 A. 相似文献