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51.
In this paper we describe the experimental analysis of a novel ion-exchange polymer metal composite (IPMC) actuator under
large external voltage. The experimental analysis is supplemented with a coupled thermodynamic model, which includes mass
transport across the thickness of the polymer actuator, chemical reactions at boundaries, and deformation as a function of
the solvent (water) distribution. In this paper, the case of large electrode potentials (over 1.2 V) has been analyzed experimentally
and theoretically. At these voltage levels, electrochemical reactions take place at both electrodes. These are used in the
framework of overpotential theory to develop boundary conditions for the water transport in the bulk of polymer. The model
is then simplified to a three-component system comprised of a fixed negatively charged polymeric matrix, protons, and free
water molecules within the polymer matrix. Among these species, water molecules are considered to be the dominant species
responsible for the deformation of the IPMC actuators. Experiments conducted at different initial water contents are described
and discussed in the context of the proposed deformation mechanism. Comparison of numerical simulations with experimental
data shows good agreement. 相似文献
52.
Jacquelyn A. Carioscia Lauren Schneidewind Casey O'Brien Robert Ely Caitlin Feeser Neil Cramer Christopher N. Bowman 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5686-5696
The ability to prepare high Tg low shrinkage thiol–ene materials is attractive for applications such as coatings and dental restoratives. However, thiol and nonacrylated vinyl materials typically consist of a flexible backbone, limiting the utility of these polymers. Hence, it is of importance to synthesize and investigate thiol and vinyl materials of varying backbone chemistry and stiffness. Here, we investigate the effect of backbone chemistry and functionality of norbornene resins on polymerization kinetics and glass transition temperature (Tg) for several thiol–norbornene materials. Results indicate that Tgs as high as 94 °C are achievable in thiol–norbornene resins of appropriately controlled chemistry. Furthermore, both the backbone chemistry and the norbornene moiety are important factors in the development of high Tg materials. In particular, as much as a 70 °C increase in Tg was observed in a norbornene–thiol specimen when compared with a sample prepared using allyl ether monomer of analogous backbone chemistry. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5686–5696, 2007 相似文献
53.
Stan J. Surma 《Logica Universalis》2007,1(1):209-219
The connection presented in this paper mirror-links two metamathematical structures, the finitary closure operators, and the
compact consistency properties, in such a way that a specification of one structure induces a provably equivalent specification
of the other.
Mathematics Subject Classification (2000): Primary 06A15, Secondary 28E10 03B22 相似文献
54.
本文研究弱一致Opial条件的性质;弱一致Opial条件与弱一致Opial条件的对偶性;证明当对偶空间有弱一致Opial条件时该Banach空间具有不动点性. 相似文献
55.
本文用超声相比较方法测定了高Tc超导体La1.85Sr0.15CuO4,La2CuO4和YBa2Cu3O7的纵波和横波声速,进而导出了它们的纵向模量、切变模量、杨氏模量、泊松比、德拜温度及定体比热。在La1.85Sr0.15CuO4样品上,还进行了压力实验,发现所有弹性模量都是随压强增加而增加。定体比热cV和泊松比σ在高压下则略有下降。德拜温度是随压强增加而增加的。 相似文献
56.
Cellulose carbamate, an environmentally friendly material presents an interesting alternative to petroleum-based polymers because of its renewable, biodegradable, biocompatible nature and its solubility in conventional solvents. In synthesis process of cellulose carbamate, urea was firstly impregnated into the cellulose pulp by supercritical CO2(scCO2), followed by the esterification of cellulose. The structure of cellulose carbamate was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The rheological properties of these cellulose carbamates in 9% sodium hydroxide solution were investigated, using a range of the nitrogen content, concentrations and shear rates. 相似文献
57.
如果一个图G存在一个k-列表安排使得G具有一个唯一列表染色,则称 G是唯一列表可染色图,简称UkLC图.我们称图G具有M(k)性质当且仅当G不 是UkLC图.本文在借鉴θr,s,t-图概念的基础上引入θr,s,t-图的定义,并证明:除了 r=s=t=2以外,θr,s,t-图都是U2LC图.利用如上结果我们给出M.Mahdian and E.S.Mahmoodian对U2LC图所作特征化的一个简单证明. 相似文献
58.
Li Taihua An Zhu Luo Zhengming Center for Radiation Physics Institute of Nuclear Science Technology Sichuan Union University Chengdu 《原子与分子物理学报》1997,(1)
MEASUREMENTSOFFeANDCuK-ShelIONIZATIONCROSSSECTIONSBYSLOWELECTRONIMPACTLiTaihuaAnZhuLuoZhengmingCenterforRadiationPhysics,Ins... 相似文献
59.
为了精确计算束流在离子光学系统中的传输,用Visual FORTRAN 6.5语言编写了一个计算程序,长约13000行. 此程序可以计算由三圆筒单透镜、三膜片单透镜、双元筒透镜、均匀场静电加速管、磁四极透镜、六极磁铁、静电四极透镜、偏转磁铁、螺线管透镜、ExB~正交电磁场分析器、静电偏转器、漂浮管、QWR(Quarter Wave Resonators)和SLR(Split Loop Resonators)射频加速元件等元件任意组成的离子光学系统. 粒子轨迹的计算可精确到三级近似. 粒子的分布类型也可以有多种选择. 程序具有最优化计算功能,即可以自动调整元件的参数,以实现所需要的光学条件. 各元件之后的横向和纵向相图以及系统的束流包络线以图形方式显示在屏幕上. 相似文献
60.
Nanocrystalline thin films of copper selenide have been grown on glass and tin doped-indium oxide substrates using chemical method. At ambient temperature, golden films have been synthesized and annealed at 200 °C for 1 h and were examined for their structural, surface morphological and optical properties by means of X-ray diffraction (XRD), scanning electron microscopy and UV-vis spectrophotometry techniques, respectively. Cu2−xSe phase was confirmed by XRD pattern and spherical grains of 30 ± 4 - 40 ± 4 nm in size aggregated over about 130 ± 10 nm islands were seen by SEM images. Effect of annealing on crystallinity improvement, band edge shift and photoelectrochemical performance (under 80 mW/cm2 light intensity and in lithium iodide electrolyte) has been studied and reported. Observed p-type electrical conductivity in copper selenide thin films make it a suitable candidate for heterojunction solar cells. 相似文献