Effect of the surface-modifying macromolecules on the duration of the surface functionalization

Functionalization of polystyrene films by the preferential surface enrichment of surface-modifying macromolecules (SMM) to achieve a hydrophilic surface with long effective duration is described. The comb-like amphiphilic copolymers (PKG-g-PS) based on styrene-maleic anhydride copolynier (SMA) backbone was synthesized by esterification of SMA with poly(ethylene glycol) (PEG). When PEG-g-PS was melt blended with polystyrene, the preferential surface enrichment of PEG-g-PS was much evident resulting in the large increase of the surface polarity. The effective duration of the surface functionalizatoin was also hugely extended as SMMs were added into the blends. Furthermore, more polyether chain segments on PEG-g-PS could selectively migrate to the surface by the inducement of polar solvent. Compared with the PEG-g-PS/PS and PEG/PEG-g-PS/PS blends, the surface polarity and the effective duration of surface modification both increased greatly when PEG-g-PS was used as the compatibilizer of PEG/PS blends. It was an effective solution to balance the conflict between the duration and efficiency of the surface-modifying additives.     

Elastic Scattering of Ultracold ^133Cs and SSRb Atoms in Triplet State

Elastic scattering properties of the ultracold interaction for the triplet state of ^133Cs and ^85Rb atoms are studied using two kinds of potentials by the same phase Ф. One is the interpolation potential, and another is Lennard-Jones potential （LJl2,6 ）. The radial Schrodtinger equation is also solved using two computational methods, the semiclassical method （WKB）, and the Numerov method. Our results are found to be in an excellent agreement with the more recent theoretical values. It shows that the two potentials and methods are applicable for studying ultracold collisions between the mixing alkali atoms.     

The <Emphasis Type="Italic">q</Emphasis>-Analogues of Squeezed States and Some Properties

In this paper we shall introduce two q-analogues of the squeezed states in terms of the technique of integration within an ordered product of operators and the properties of the inverses of q-deformed annihilation and creation operators, and some nonclassical properties of the states are examined. Furthermore, we obtain some new completeness relations composed of the bra and ket which are not mutually Hermitian conjugate. PACS numbers: 03.65.-w; 45.50.Ct. Work supported by the National Natural Science Foundation of China under Grant 10574060 and the Natural Science Foundation of Shandong Province of China under Grant Y2004A09.     

干涉条纹边缘检测方法的比较与改进

研究了干涉条纹边缘检测中的Sobel算子和Laplacian算子,针对二者使干涉条纹变粗和模糊的现象,提出了改进的Laplacian算子。该改进算子先对干涉条纹利用Gauss函数进行平滑,然后再作Laplacian变换。实验结果表明,改进的Laplacian算子克服经典算子的不足,获得清晰的条纹边缘,满足了干涉条纹后续处理要求。     

Combined implementing the hole-drilling method and reflection hologram interferometry for residual stresses determination in cylindrical shells and tubes

Main features inherent in simplified approach to residual stresses determination in cylindrical shells and tubes, external diameter of which is not less than 60 mm, by combing the hole-drilling method and reflection hologram interferometry are discussed in detail. Initial experimental information in a form of hole diameter increments in principal stress directions is derived from high-quality reflection holograms recorded near cylindrical objects of intermediate curvature value. Converting measured parameters into required stress values is based on the transition model that corresponds to plane stress conditions of pure membrane type. The technique developed is capable of determining residual stress component values within 5% accuracy in an absence of stress gradients over the probe hole diameter when a type of residual stress field corresponds to the transition model adopted. The accuracy analysis involved is based on matrix formulation of conventionally direct problem and an assumption on a pure membrane character of residual stress field under study for thin-walled shell. Required error estimations in a case of inspecting thick-walled cylindrical tube are obtained by combining the above-mentioned approach and an analogy of reconstructed fringe patterns with actual and artificial interferograms, which follow from drilling blind hole of the same geometrical parameters in thick-walled plates. Experimental verification of the developed approach is founded upon a determination of actual stresses in thin-walled cylindrical shell and obtaining residual stress distributions at the proximity of welded joint in thick-walled cylindrical tube.     

High sensitivity CW-Cavity Ring Down Spectroscopy of N2O near 1.5 μm (II)

We present the second part of the investigation of the high sensitivity absorption spectrum of nitrous oxide by CW-Cavity Ring Down Spectroscopy near 1.5 μm. In a first paper [A.W. Liu, S. Kassi, P. Malara, D. Romanini, V.I. Perevalov, S.A. Tashkun, S.M. Hu, A. Campargue, J. Mol. Spectrosc. 244 (2007) 33-47] devoted to the 6000-6833 cm⁻¹ region, more than 6000 line positions of five isotopologues (¹⁴N₂¹⁶O, ¹⁵N¹⁴N¹⁶O, ¹⁴N¹⁵N¹⁶O, ¹⁴N₂¹⁷O, and ¹⁴N₂¹⁸O), were rovibrationally assigned to a total of 68 bands. The achieved noise equivalent absorption (α_min ∼ 2 × 10⁻¹⁰ cm⁻¹) allowed for the detection of lines with intensity weaker than 2 × 10⁻²⁹ cm/molecule. In this contribution, the investigated region was extended down to 5905 cm⁻¹ and additional recordings allowed accessing small spectral sections uncovered in our preceding recordings. A deeper analysis based on the predictions of the effective Hamiltonian model has allowed assigning a total of 3149 transitions and lowering the percentage of lines left unassigned from 51% to 28%. It led to the analysis of 35, 6, 7, and 6 bands for the ¹⁴N₂¹⁶O, ¹⁵N¹⁴N¹⁶O, ¹⁴N¹⁵N¹⁶O, and ¹⁴N₂¹⁸O isotopologues, respectively. Forty-two of these 54 bands are newly observed, while the rotational analysis of the twelve others is significantly extended and improved. Most of the bands were found unperturbed and their line positions could be reproduced within the experimental uncertainty (about 1 × 10⁻³ cm⁻¹). The corresponding spectroscopic parameters are reported. Local rovibrational perturbations induced by either intrapolyad or interpolyad couplings were found to affect five hot bands of ¹⁴N₂¹⁶O. Their detailed analysis is presented.     

单分子器件与电极间耦合界面对电子传输的影响

利用自恰tight-binding 理论，对由phenalenyl分子构成的全对称三电极纳米单分子器件的电子传导特性进行了理论研究. 通过改变电极与分子界面上的耦合，得出了分子与原子线电极间耦合强度变化对电子传输的影响. 结果显示电子通过phenalenyl分子器件的概率随着分子与电极的耦合强度变弱而减小. 当耦合强度变大时，不仅电子通过phenalenyl分子器件的概率变大，而且在较宽的能带内电子都可以通过phenalenyl分子. 所得结果还揭示出在特定的能区，对称三电极phenalenyl分子可以构成一个无源正负能量开关器件的新特性.     

Lactic acid‐ and carbonate‐based crosslinked polymeric micelles for drug delivery

Our objective was to synthesize and evaluate lactic acid‐ and carbonate‐based biodegradable core‐ and core‐corona crosslinkable copolymers for anticancer drug delivery. Methoxy poly(ethylene glycol)‐b‐poly(carbonate‐co‐lactide‐co‐5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxane‐2‐one) [mPEG‐b‐P(CB‐co‐LA‐co‐MAC)] and methoxy poly(ethylene glycol)‐b‐poly(acryloyl carbonate)‐b‐poly(carbonate‐co‐lactide) [mPEG‐b‐PMAC‐b‐P(CB‐co‐LA)] copolymers were synthesized by ring‐opening polymerization of LA, CB, and MAC using mPEG as an macroinitiator and 1,8‐diazabicycloundec‐7‐ene as a catalyst. These amphiphilic copolymers which exhibited low polydispersity and critical micelle concentration values (0.8–1 mg/L) were used to prepare micelles with or without drug and stabilized by crosslinking via radical polymerization of double bonds introduced in the core and interface to improve stability. mPEG₁₁₄‐b‐P(CB₈‐co‐LA₃₅‐co‐MAC_2.5) had a higher drug encapsulation efficiency (78.72% ± 0.15%) compared to mPEG₁₁₄‐b‐PMAC_2.5‐b‐P(CB₉‐co‐LA₃₉) (20.29% ± 0.11%).¹H NMR and IR spectroscopy confirmed successful crosslinking (～70%) while light scattering and transmission electron microscopy were used to determine micelle size and morphology. Crosslinked micelles demonstrated enhanced stability against extensive dilution with aqueous solvents and in the presence of physiological simulating serum concentration. Furthermore, bicalutamide‐loaded crosslinked micelles were more potent compared to non‐crosslinked micelles in inhibiting LNCaP cell proliferation irrespective of polymer type. Finally, these results suggest crosslinked micelles to be promising drug delivery vehicles for chemotherapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

有界闭区间上连续函数的平均值问题的良定性

给出了函数的平均值问题的良定性概念,并证明了有界闭区间上连续函数的平均值问题是G-wp和GLP-wp的等结论.     

THE EFFECT OF BILINEAR BEHAVIOUR ON THE DIRECTION AND MAGNITUDE OF THE PEELING MOMENT IN A BI-MATERIAL BEAM

In this work a bi-material beam exhibiting partly bilinear behaviour under a uniform temperature change is analyzed. The essence of solution is based on the approach of Timoshenko’s mechanics of materials. The main aim of the present analysis is to understand the effect of the bilinear behaviour on the peeling moment. This theoretical mechanics model mentioned here can give us useful insights to improve the resistance against the delamination.