Mechanical behavior and wrinkling patterns of phase-separated binary polymer blend film

The wrinkling of phase-separated binary polymer blend film was studied through combining the Monte Carlo (MC) simulation for morphologies with the lattice spring model (LSM) for mechanical properties. The information of morphology and structure obtained by use of MC simulation is input to the LSM composed of a three-dimensional network of springs, which allows us to determine the wrinkling and the mechanical properties of polymer blend film, such as strain, stress, and Young’s modulus. The simulated results show that the wrinkling of phase-separated binary polymer blend film is related not only to the structure of morphology, but also to the disparity in elastic moduli between polymers of blend. Our simulation results provide fundamental insight into the relationship between morphology, wrinkling, and mechanical properties for phase-separated polymer blend films and can yield guidelines for formulating blends with the desired mechanical behavior. The wrinkling results also reveal that the stretching of the phase-separated film can form the micro-template, which has a wide application prospect.     

A field-reversal method for measuring the parameters of a ferroelectric liquid crystal

A method for measuring the spontaneous polarization P _s, the switching time, the rotational viscosity γ_φ, and the d.c. conductivity σ is presented. The possibilities of estimating the azimuthal angle φ₀, the dielectric anisotropy δε and the dielectric permittivity ε_⊥ in the same experiment are also discussed. It is explicitly shown that the switching delay, though primarily dependent on the material and the applied field, is also dependent on the geometry of the cell.     

一维异核配合物[KNd(bta)2(H2O)6]·H2O的水热合成，晶体结构和荧光性质

以双四唑胺(H₂bta)、NdCl₃·6H₂O、KOH为原料,用水热法合成了1个一维异核的Nd³⁺配合物[KNd(bta)₂(H₂O)₆]·H₂O。通过X-射线单晶衍射、元素分析、红外光谱对该配合物进行了结构表征。该化合物属于单斜晶系,P2₁/m空间群。每个Nd³⁺与2个来自bta^2-离子的4个氮原子和5个水分子形成了1个盖帽的四方双锥,通过bta^2-和水分子桥联配体把Nd³⁺和K⁺连接成一维链状结构,链与链之间通过O-H…N和N-H…O氢键作用形成三维超分子结构。紫外吸收光谱和荧光光谱表征结果显示该配合物的水溶液在292和412 nm表现出双四唑胺的特征吸收峰和荧光发射特征峰。     

炭化处理高烧失量硅藻土及对天然橡胶的性能补强

通过缺氧条件下煅烧富含有机质的内蒙硅藻土制备了一种含炭的硅藻土,并将这种炭化硅藻土代替部分炭黑用于天然橡胶的补强.采用红外光谱、X射线衍射、热分析、扫描电子显微镜、能谱和万能材料试验机对炭化硅藻土进行结构表征和力学性能测试.结果表明,于600℃进行2h的缺氧锻烧处理后,硅藻土中的有机质已经转化为无定形碳紧密吸附于硅藻土...     

Electronic Properties of Passive Films Formed on G3 and G30 Nickel-based Alloys in Bicarbonate/Carbonate Buffer Solution

The electronic properties of passive films formed on G3 and G30 alloys in bicarbonate/carbonate buffer solution were comparatively studied by electrochemical impedance spectra(EIS) and Mott-Schottky analysis, the chemical composition of the passive film formed on G3 alloy was detected by X-ray photoelectron spectroscopy (XPS). The results show that passive film on G3 alloy had better protection than that on G30 alloy. The transfer resistance, film resistance and diffusion resistance of the passive films on ...     

稀土氧化物上SO2和NO的催化还原(Ⅲ)──用CO作还原剂的同步脱硫和脱氮

考察了稀土系列氧化物作为CO同步还原SO₂和NO催化剂的活性.结果表明,氧化钐和氧化钕表现了最高的活性,在475℃,SO₂和NO的转化率同时超过95%.实验发现稀土氧硫化物是活性相.通常脱硫活性高的样品同样具有高的脱氮活性,但CeO₂表现了不同的行为,其脱硫活性虽低,但脱氮活性却较高.文中还对同步反应的机理作了探讨,发现COS不仅是还原SO₂的中间物,同时也是还原NO的中间物.结合活性相和反应机理对不同稀土氧化物的活性差异作了讨论.     

Sm金属富勒烯的高效提取和电化学性质研究

在金属富勒烯 [1]的形成过程中 ,存在从金属到碳笼的电子转移 .La系金属富勒烯中 ,金属原子转移 2或 3个电子给碳笼形成 + 2或 + 3价的金属离子和带有大量负电荷的碳笼 .尽管如此 ,金属富勒烯仍具有良好的接受电子的能力 [2 ,3] .大多数的 La系金属富勒烯 ( Y,La,Ce,Pr,Nd,Gd,Tb,Dy,Ho,Er,L u)的电化学方法研究表明 ,它们可以接受 5到 6个电子 ,但是 ,Sm的金属富勒烯的氧化还原性质尚未见报道 ,其主要原因是 Sm金属富勒烯的合成产率低 ,仅是 La金属富勒烯的 7% ,从而使得其分离非常困难 ,需要通过多步 HPLC循环才能得到 [4 ,5] ,高…     

Two-photon absorption in quadrupolar pi-conjugated molecules: influence of the nature of the conjugated bridge and the donor-acceptor separation

Quadrupolar-type substitution of pi-conjugated chromophores with donor and acceptor groups has been shown to increase their two-photon absorption (TPA) response by up to two orders of magnitude. Here, we apply highly correlated quantum-chemical calculations to evaluate the impact of the nature of conjugated bridge and the charge-transfer distance on that enhancement. We compare chromophores with phenylenevinylene-, thienylenevinylene-, polyene-, and indenofluorene-type backbones substituted by dimethylamino and cyano groups. In all compounds, we find a strongly TPA-active A(g) state (either 2A(g) or 3A(g)) in the low-energy region, as well as a higher lying TPA-active state (mA(g)) at close to twice the energy of the lowest lying one-photon allowed state; the smaller energy detuning in the mA(g) states results in very large TPA cross sections delta. We also investigate the influence of the degree of ground-state polarization on TPA. Independent of the nature of the backbone and the donor-acceptor separation, delta displays the same qualitative evolution with a maximum before the cyanine-like limit; the highest TPA cross sections are calculated for distirylbenzene- and polyene-based systems.     

Observation on meta-stability of thulium nitrate crystal by using electric measurements

Frequency dependence of ac conductivity from 1 to 10⁵ Hz and time series of the conductivity at 2 kHz were measured along c-axis of thulium nitrate crystal, Tm(NO₃)₃6H₂O at temperatures from 203.15 to 293.15 K. The meta-stability was observed. The frequency spectra of the conductivity were similar to those in disorder system. Aging effect was observed. Non-periodic instability (burst) was found. Non-linear dynamical property was characterized by 1/f noise spectrum, limit cycle in return map and dependence of correlation exponent on embedding dimension.     

Surface composition and property of film prepared with aqueous dispersion of polyurethaneurea-acrylate including fluorinated block copolymer

The aqueous dispersion of polyurethaneurea-acrylate (PUA) including small amount of fluorinated block copolymers containing carboxyl groups (PATF), which can be dissolved in water, was used to make films and the surface properties of these films were examined. The experimental data show that the modified PUA film exhibits a hydrophobic surface property, although the original surface of PUA film is hydrophilic. The surface composition of the modified PUA film was measured by ATR and XPS. The results indicate that there is a concentration gradient of the fluorine groups along the lines of thickness of the modified film and towards the outmost surface layer, resulting from the migration of fluorinated blocks to the air side surface of the modified PUA film during the film formation process. However, the PUA film can not be modified effectively by adding the sodium salt of PATF, since the urethane groups in the system are easy to occupy on the surface of the film.