应用显微技术观察未涂布纸中墨滴渗透图像的研究

摘译 墨滴在纸页结构中的渗吸是一个非常复杂的过程.纸页中的孔隙以纳米级尺寸存在于纤维(纤维之间或几微米的大孔径)及其细胞壁中.墨滴的渗吸过程包括纤维间孔隙的毛细管作用、在纤维内部和细胞壁微孔中的渗透,以及沿纤维的表面扩散.喷墨墨滴大小只达到皮升级,因此纤维的芯吸效应和墨水在纤维表面的扩散起主要作用.     

Hydrogen embrittlement associated with strain localization in a precipitation-hardened Fe–Mn–Al–C light weight austenitic steel

Hydrogen embrittlement of a precipitation-hardened Fe–26Mn–11Al-1.2C (wt.%) austenitic steel was examined by tensile testing under hydrogen charging and thermal desorption analysis. While the high strength of the alloy (>1 GPa) was not affected, hydrogen charging reduced the engineering tensile elongation from 44 to only 5%. Hydrogen-assisted cracking mechanisms were studied via the joint use of electron backscatter diffraction analysis and orientation-optimized electron channeling contrast imaging. The observed embrittlement was mainly due to two mechanisms, namely, grain boundary triple junction cracking and slip-localization-induced intergranular cracking along micro-voids formed on grain boundaries. Grain boundary triple junction cracking occurs preferentially, while the microscopically ductile slip-localization-induced intergranular cracking assists crack growth during plastic deformation resulting in macroscopic brittle fracture appearance.     

Synthetic Hydrophilic Materials with Tunable Strength and a Range of Hydrophobic Interactions

The ability to vary, adjust, and control hydrophobic interactions is crucial in manipulating interactions between biological objects and the surface of synthetic materials in aqueous environment. To this end a grafted polymer layer (multi‐component mixed polymer brush) is synthesized that is capable of reversibly exposing nanometer‐sized hydrophobic fragments at its hydrophilic surface and of tuning, turning on, and turning off the hydrophobic interactions. The reversible switching occurs in response to changes in the environment and alters the strength and range of attractive interactions between the layer and hydrophobic or amphiphilic probes in water. The grafted layer retains its overall hydrophilicity, while local hydrophobic forces enable the grafted layer to sense and attract the hydrophobic domains of protein molecules dissolved in the aqueous environment. The hydrophobic interactions between the material and a hydrophobic probe are investigated using atomic force microscopy measurements and a long‐range attractive and contact‐adhesive interaction between the material and the probe is observed, which is controlled by environmental conditions. Switching of the layer exterior is also confirmed via protein adsorption measurements.     

Enzyme-based logic systems and their applications for novel multi-signal-responsive materials

Recent advances in biochemical logic systems and their integration with signal-responsive materials to yield "smart" hybrid systems are briefly outlined in the paper.     

Model of coating wear degradation in precision glass molding

Coatings in precision glass molding (PGM) experience severe thermo-chemical and thermo-mechanical loads during several hundred or thousand pressing cycles. Until now, little is known about the integrity loss of protective coatings for these applications. Gaining knowledge of fundamental mechanisms on the functional degradation of protective coatings is of great interest. The work presented in this paper investigates compositional changes in the surface-near region of precious metal PVD-coatings after being annealed in hot glass contact. Different characteristic wear zones identified on the samples have been analyzed by light microscopy, SEM/EDX, as well as X-ray photoelectron spectroscopy (XPS). The results are compared to the wear stages observed on molds used in industrial production. A qualitative model for the degradation of the substrate-coating system is proposed, ranging from the initial phases of material alteration to the final coating breakdown. In addition, indications that glass components might play a role in the overall degradation process were found but could not be revealed in detail. With regards to highly precise molding tools for PGM, further work should be focused on the initial phase of wear, since the end of service life time is reached at early degradation stages, far before the coating flake-off.     

Quantifying structural attributes of system decompositions in 28 feature-oriented software product lines

A key idea of feature orientation is to decompose a software product line along the features it provides. Feature decomposition is orthogonal to object-oriented decomposition—it crosscuts the underlying package and class structure. It has been argued often that feature decomposition improves system structure by reducing coupling and by increasing cohesion. However, recent empirical findings suggest that this is not necessarily the case. In this exploratory, observational study, we investigate the decompositions of 28 feature-oriented software product lines into classes, features, and feature-specific class fragments. The product lines under investigation are implemented using the feature-oriented programming language Fuji. In particular, we quantify and compare the internal attributes import coupling and cohesion of the different product-line decompositions in a systematic, reproducible manner. For this purpose, we adopt three established software measures (e.g., coupling between units, CBU; internal-ratio unit dependency, IUD) as well as standard concentration statistics (e.g., Gini coefficient). In our study, we found that feature decomposition can be associated with higher levels of structural coupling in a product line than a decomposition into classes. Although coupling can be concentrated in very few features in most feature decompositions, there are not necessarily hot-spot features in all product lines. Interestingly, feature cohesion is not necessarily higher than class cohesion, whereas features are more equal in serving dependencies internally than classes of a product line. Our empirical study raises critical questions about alleged advantages of feature decomposition. At the same time, we demonstrate how our measurement approach of coupling and cohesion has potential to support static and dynamic analyses of software product lines (i.e., type checking and feature-interaction detection) by facilitating product sampling.     

Reflection of light by composite volume holograms: Fresnel corrections and Fabry-Perot spectral filtering

Effects in composite volume Bragg gratings (VBGs) are studied theoretically and experimentally. The mathematics of reflection is formulated with a unified account of Fresnel reflections by the boundaries and of VBG reflection. We introduce the strength S of reflection by an arbitrary lossless element such that the intensity of reflection is R=tanh(2) S. We show that the ultimate maximum/minimum of reflection by a composite lossless system corresponds to addition/subtraction of relevant strengths of the sequential elements. We present a new physical interpretation of standard Fresnel reflection: strength for TE or for TM reflection is given by addition or by subtraction of two contributions. One of them is an angle-independent contribution of the impedance step, while the other is an angle-dependent contribution of the step of propagation speed. We study an assembly of two VBG mirrors with a thin immersion layer between them that constitutes a Fabry-Perot spectral filter. The transmission wavelength of the assembly depends on the phase shift between the two VBGs. Spectral resolution Deltalambda(FWHM)=25 pm at lambda=1063.4 nm is achieved with the device of small total physical thickness 2L=5.52 mm.