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941.
942.
P. N. Zhukova T. H. Le V. A. Nasonova N. N. Nasonov V. I. Sergienko 《Bulletin of the Lebedev Physics Institute》2013,40(4):83-85
The possibility of the determination of the position of an atom incorporated in the crystal unit cell by measuring the yield of characteristic radiation of this atom, excited by an X-ray wave nonuniform over the cell cross section, is shown. Such a wave can appear, in particular, in the mode of dynamical diffraction of an ordinary plane wave. 相似文献
943.
Multiaxial mechanical behavior of aramid fibers and identification of skin/core structure from single fiber transverse compression testing 下载免费PDF全文
Judith Wollbrett‐Blitz Sébastien Joannès Rémi Bruant Christophe Le Clerc Marc Romero De La Osa Anthony Bunsell Alba Marcellan 《Journal of Polymer Science.Polymer Physics》2016,54(3):374-384
The transverse and longitudinal mechanical properties of aramid fibers like Kevlar? 29 (K29) fibers are strongly linked to their highly oriented structure. Mechanical characterization at the single fiber scale is challenging especially when the diameter is as small as 15 µm. Longitudinal tensile tests on single K29 fibers and single fiber transverse compression test (SFTCT) have been developed. Our approach consists of coupling morphological observations and mechanical experiments with SFTCT analysis by comparing analytical solutions and finite element modeling. New insights on the analysis of the transverse direction response are highlighted. Systematic loading/unloading compression tests enable to experimentally determine a transverse elastic limit. Taking account of the strong anisotropy of the fiber, the transverse mechanical response sheds light on a skin/core architecture. More importantly, results suggest that the skin of the fiber, typically representing a shell of one micrometer in thickness, has a transverse apparent modulus of 0.2 GPa. That is around more than fifteen times lower than the transverse modulus of 3.0 GPa in the core. By comparison, the measured longitudinal modulus is about 84 GPa. The stress distribution in the fiber is explored and the critical areas for damage initiation are discussed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 374–384 相似文献
944.
Redox‐responsive core cross‐linked micelles of poly(ethylene oxide)‐b‐poly(furfuryl methacrylate) by Diels‐Alder reaction for doxorubicin release 下载免费PDF全文
Cuong M. Q. Le Hai Ha Pham Thi Xuan Thang Cao Gun‐Do Kim Chul‐Woong Oh Kwon Taek Lim 《Journal of polymer science. Part A, Polymer chemistry》2016,54(23):3741-3750
Redox‐responsive core cross‐linked (CCL) micelles of poly(ethylene oxide)‐b‐poly(furfuryl methacrylate) (PEO‐b‐PFMA) block copolymers were prepared by the Diels‐Alder click‐type reaction. First, the PEO‐b‐PFMA amphiphilic block copolymer was synthesized by the reversible addition‐fragmentation chain transfer polymerization. The hydrophobic blocks of PFMA were employed to encapsulate the doxorubicin (DOX) drug, and they were cross‐linked using dithiobismaleimidoethane at 60 °C without any catalyst. Under physiological circumstance, the CCL micelles demonstrated the enhanced structural stability of the micelles, whereas dissociation of the micelles took place rapidly through the breaking of disulfide bonds in the cross‐linking linkages under reduction environment. The core‐cross‐linked micelles showed fine spherical distribution with hydrodynamic diameter of 68 ± 2.9 nm. The in vitro drug release profiles presented a slight release of DOX at pH 7.4, while a significant release of DOX was observed at pH 5.0 in the presence of 1,4‐dithiothreitol. MTT assays demonstrated that the block copolymer did not have any practically cytotoxicity against the normal HEK293 cell line while DOX‐loaded CCL micelles exhibited a high antitumor activity towards HepG2 cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3741–3750 相似文献
945.
Two water‐soluble 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino (pzta)‐based Cu(II) complexes, namely [Cu(l ‐Val)(pzta)(H2O)]ClO4 ( 1 ) and [Cu(l ‐Thr)(pzta)(H2O)]ClO4 ( 2 ) (l ‐Val: l ‐valinate; l ‐Thr: l ‐threoninate), were synthesized and characterized using elemental analyses, molar conductance measurements, spectroscopic methods and single‐crystal X‐ray diffraction. The results indicated that the molecular structures of the complexes are five‐coordinated and show a distorted square‐pyramidal geometry, in which the central copper ions are coordinated to N,N atoms of pzta and N,O atoms of amino acids. The interactions of the complexes with DNA were investigated using electronic absorption, competitive fluorescence titration, circular dichroism and viscosity measurements. These studies confirmed that the complexes bind to DNA through a groove binding mode with certain affinities (Kb = 4.71 × 103 and 1.98 × 103 M?1 for 1 and 2 , respectively). The human serum albumin (HSA) binding properties of the complexes were also evaluated using fluorescence and synchronous fluorescence spectroscopies, indicating that the complexes could quench the intrinsic fluorescence of HSA in a static quenching process. The relevant thermodynamic parameters revealed the involvement of van der Waals forces and hydrogen bonds in the formation of complex–HSA systems. Finally, molecular docking technology was also used to further verify the interactions of the complexes with DNA/HSA. 相似文献
946.
947.
Energy management in buildings is addressed in this paper. The energetic impact of buildings in the current energetic context
is first depicted. Then the studied optimization problem is defined as the optimal management of production and consumption
activities in houses. A scheduling problem is identified to adjust the energy consumption to both the energy cost and the
inhabitant’s comfort. The available flexibilities of the services provided by domestic appliances are used to compute optimal
energy plans. These flexibilities are associated to time windows or heating storage abilities. A constraints formulation of
the energy allocation problem is given. A derived mixed linear program is used to solve this problem. The energy consumption
in houses is very dependent to uncertain data such as weather forecasts and inhabitants’ activities. Parametric uncertainties
are introduced in the home energy management problem in order to provide robust energy allocation. Robust linear programming
is implemented. Event related uncertainties are also addressed through stochastic programming in order to take into account
the inhabitant’s activities. A scenario based approach is implemented to face this robust optimization problem. 相似文献
948.
马惠琼 《大连民族学院学报》2014,16(2):183-185
民族高校的地缘和生源特点等诸多因素,决定了教师在开展大学英语教学过程中必须采用适合自身特点的教学模式和教学策略。任务型教学法从学生的基本心理需求出发,强调用语言做事,注重学生交际能力的培养,符合大学英语现行的培养目标。从分析任务型教学法的特点以及任务型教学实践入手,阐述了任务型教学法在民族高校大学英语教学中的重要作用。 相似文献
949.
a four-step synthesis of monoalkylated benzidin is reported for immunogen preparation against benzidin dye. Use of 10% H2SO4/ dioxan for N-Boc cleavage avoids the cyclisation of 4-benzidinyl butyric acid into the corresponding lactam observed with the classical TFA/ CH2Cl2 system. 相似文献
950.
C. C. MA H. Garreau D. R. Squire V. T. Stannett M. A. Littlejohn 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9):1613-1620
Ethoxy methyl carbenium hexachioroantimonate has been synthesized as a model compound for the propagating species in the cationic polymerization of the vinyl ethers. Its degree of dissociation in methylene chloride has been studied as a function of concentration by using the method described in Part I. A simple one two dissociation was found. The degree of dissociation, however, was less than that found with a typical initiator such as triphenyl methyl hexachioroantimonate. 相似文献