Cauchy-Poisson Problem for a Two-layer Fluid with an Inertial Surface

This paper is concerned with the generation of waves due to initial disturbances at the upper surface of a two-layer fluid, as the upper layer is covered by an inertial surface and the lower layer extends infinitely downwards. The inertial surface is composed of thin but uniform distribution of non-interacting material. In the mathematical analysis, the Fourier and Laplace transform techniques have been utilized to obtain the depressions of the inertial surface and the interface in the form of infinite integrals. For initial disturbances concentrated at a point, the inertial surface depression and the interface depression are evaluated asymptotically for large time and distance by using the method of stationary phase. They are also depicted graphically for two types of initial disturbances and appropriate conclusions are made.

3D Layout Algorithm for Laying Rectangular Tiles on Ship Hull

A new 3D layout algorithm to lay rectangular tiles on the 3D hull surface model is proposed to improve the algorithm performance in accelerating layout process and enhancing design accuracy. Three times optimizations are carried out upon the original basic algorithm, namely optimization of calculating range, separation of surface flattening computation from laying computation, and optimization of interior point distribution. By testing, the generated surface layout drawing by the refined system is fairly applicable to guide the actual tiles＇ coating process.

Why a mosquito leg possesses superior load-bearing capacity on water:Experimentals

Mosquitoes possess the striking ability to walk on water because each of their legs has a huge water supporting force（WSF） that is 23 times their body weight.Aiming at a full understanding of the origins of this extremely large force,in this study,we concentrate on two aspects of it：the intrinsic properties of the leg surface and the active control of the initial stepping angle of the whole leg.Using a measurement system that we developed ourselves,the WSFs for the original leg samples are compared with those whose surface wax and microstructures have been removed and with those of a different stiffness.The results show that leg f exibility plays a dominant role over surface wax and microstructures on the leg surface in creating the supporting force.Moreover,we discuss the dependence relationship between the maximum WSF and the initial stepping angle,which indicates that the mosquito can regulate this angle to increase or decrease the WSF during landing or takeoff.These finding are helpful for uncovering the locomotion mechanism of aquatic insects and for providing inspiration for the design of microfluids miniature boats,biomimetic robots,and microsensors.

Ultrasensitive Electrochemical Aptasensor Based on Surface-Initiated Enzymatic Polymerization

Coupled with the ability of fast and quantitative response, electrochemical aptasensors （EA） have great potential in the application of early diagnosis of cancer biomarker. In order to determine the rare hiomarkers in the compli- cate clinical samples, scientists are making unremitting efforts towards improving the sensitivity and selectivity of EA. Herein, a ＂sandwich＂-strucmre electrochemical aptasensor （SEA） is developed for analysis of cancer biomarker carcino-embryonic antigen （CEA）. Two DNA aptamers are employed, one of which is thiolated at Y-terminal and immobilized onto the gold electrode as a capture probe, while the other one is served as signal probe. The two ap- tamers could ＂sandwich＂ the target and signal probe is then subjected to the terminal deoxynucleotidyl transferase （TdT）-catalyzed incorporation of biotin labeled dNTPs into its 3＇-terminal. Thus the as-generated long DNA oligo tails allow specific binding of numerous avidin modified horseradish peroxidase （Av-HRP）, resulting in enhanced peroxidase catalyzed electrochemical signals. This signal amplification strategy is termed as surface initiated enzy- matic polymerization （SIEP）. This SIEP amplified SEA has a detection limit of 10 pg·mL^-1, indicating the out- standing amplification efficiency.

Synthesis of Chlorogenic Acid Imprinted Chromatographic Packing by Surface-initiated Atom Transfer Radical Polymerization and Its Application

A novel chromatographic packing of chlorogenic acid（CGA） molecularly imprinted polymer（MIP） based on the 5.0 ~tm silica was prepared by surface initiated atom transfer radical polymerization（SI-ATRP） with 4-vinylpyridine（4-VP） as functional monomer, ethyl glycol dimethacrylate（EDMA） as cross-linker in the mixture of methanol and water（7：3, volume ratio） under mild reaction conditions. The characteristics of CGA MIP were investi- gated by elemental analysis, thermogravimetric analysis（TGA）, Fourier transform infrared spectrometry（FTIR） and atomic force microscopy（AFM）. The effects of some chromatographic conditions such as mobile phase composition and temperature on the retention time were investigated. The adsorption capacity of the stationary phase for com- pounds was determined by frontal chromatographic technique. The results show that Freundlich isotherm fits the ex- perimental adsorption isotherm data better than Langmuir model does. The relatively high heterogeneity index values regressed with the Freundlich isotherm suggest the formation of fairly homogeneous MIP. Thermodynamic data（AAH and AAS） obtained by van＇t Hoff plots reveal an entropy-controlled separation. The CGA MIP column was shown to be successful for the separation and purification of chlorogenic acid from the extract of Honeysuckle.

Duality of the fatigue behavior and failure mechanism in notched specimens of Ti-7Mo-3Nb-3Cr-3Al alloy

An interesting phenomenon of dual S-N fatigue behavior is investigated in a metastable β titanium alloy,Ti-7 Mo-3 Nb-3 Cr-3 Al notched cylindrical specimens with an elastic stress concentration factor of Kt=3.Fractographic studies revealed all specimens,and irrespective of lifetime,failed from the specimen surface because of stress concentration occurs at the notch root.Typically,the short-life-distribution is usually associated with surface-failure-without-facets and the long-life-distribution generally occurs due to surface-failure-with-facets.This competing failure leads to increasing the variability in fatigue lifetime and further facilitates the difficulty in prediction of fatigue lifetime.Crack-initiation area characterization was conducted by using mechanical grinding,focused ion beam milling and subsequent electron backscattered diffraction(EBSD) analysis of the 2 D section across faceted grains.Results show that the α_p particles(especially the elongated α_p particles) well-oriented for basal slip activation is a preferential fatigue-critical microstructural configuration.Additionally,the β+α_s matrix has a higher KAM value than the α_p particles in fatigued microstructures and significant dislocation activity in the form of dislocation tangles is observed in α_p boundaries.

A study of chemical reactions in coarse-grained simulations

We introduce a reaction model for use in coarse-grained simulations to study the chemical reactions in polymer systems at mesoscopic level.In this model,we employ an idea of reaction probability in control of the whole process of chemical reactions.This model has been successfully applied to the studies of surface initiated polymerization process and the network structure formation of typical epoxy resin systems.It can be further modified to study different kinds of chemical reactions at mesoscopic scale.