Thermodynamics of interaction between sodium bis(2‐ethylhexyl) sulfosuccinae and polymers in aqueous solutions by isothermal titration microcalorimetry

The interactions between sodium bis(2‐ethylhexyl) sulfosuccinae (AOT) and two nonionic water‐soluble polymers, including polyvinyl pyrrolidone (PVP) and polyethylene glycol (PEG) have been investigated by using isothermal titration microcalorimetry in aqueous solutions at 298.15 K. The results show that the critical aggregation concentration, which corresponding to the first turning point in the curve of experimental interaction heat versus concentration of the surfactant, is lower than the critical micellar concentration (cmc), confirming the existence of polymer‐surfactant interactions. The value of cac is not sensitive to the relative amount of polymer in low concentration range of the polymer. The mono‐layer saturated adsorption concentration, which corresponding to the second turning point, rises as the polymer concentration is increased. The interaction between PVP and AOT is stronger than that between PEG and AOT. The results also indicate that the aggregation of AOT in water and polymers solutions is entropically driven. The observed thermal effects have been interpreted in terms of the interactions of the polymer molecules with AOT monomers or the molecular clusters. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 275–283, 2006     

Laser beam alignment by fast feedback control of both linear and angular drifts

A new way to enhance the directional stability of laser beams with alternating intensity by fast feedback control of both linear and angular drifts has been proposed for alignment of laser beams at higher accuracy. Both linear and angular drifts of laser beams, processed through light intensity modulation and primary alignment using single-mode optical fiber (SMOF), are separated using light path arrangement and detected using phase-lock technique, and are controlled using fast feedback control mechanisms according to their detected magnitudes, so that both linear and angular drifts are suppressed to enhance the directional stability of the emitting laser beams. Theoretical analyses and preliminary experimental results indicate that the approach proposed can be used to achieve an alignment accuracy of more than 10⁻⁸ rad.     

《道德经》对高等学校管理的启示

本文从无为而治、人本管理、柔性管理、创造安定团结的学校环境、领导者的个人能力和修养五个方面分析《道德经》对高等学校管理的借鉴作用。     

纳米压印光刻中的多步定位研究

在步进重复式压印光刻中，为了避免承片台支撑绞链结构间隙及微观姿态调整往返运动导致的表面材料不规则形变，建立了单调、无振荡、多步逼近目标位置的宏微两级驱动系统，并提出了径向基函数一比例、积分、微分（RBF-PID）及单调位置控制算法．控制结果证明，使用具有强鲁棒性的RBF-PID非线性控制模式，使得驱动过程呈现无超调、无振荡的单调过程，因此避免了由于系统微观振荡调节而引入的间隙误差和材料表面形变误差．此控制方式可使步进重复式压印系统的定位精唐左满足100mm行程驱动的前提下，达到小干10nm的定位枝术指标．     

KINETIC STUDY OF THE OXIDATIVE COUPLING OF METHANE OVER La_2O_3/BaSO_4 CATALYST

IntroductionOxidativccouplingofmethanc(0CM)hasbccnthcsubjcctofmuchintcrcstrcccntl}Man}'mctaloxides,alkali-mctaI-promotcdmctaloxidcs-mixcdmcta1oxidcsandchlorinc-prom0tedmCtuloxidcshavcbecnf0undtobcactivcfor0CMHot` cvcr.thcrcisatprcscntnoclearagreemcntaboutthcmcchanismofthecouplingrcaction.T\`omodclsll1.thcthdeal-rcdoxandthcLangmuir-Hinshtt-oodmcchanisms.havcbccndcvcIopcdtodcscr1bc0CMreation-thecsscntialdiffercnccbctt"ccnthctt"omodclsisthatthclattcrinvolvcsadsorbedmothancasarcactionintcrmcd…     

FIR spectroscopy of ethyl bromide and trioxane: New laser transitions and assignments

Eight new optically pumped far infrared laser transitions from ethyl bromide and 22 from trioxane are presented. For each new line we give the wavelength, the polarization relative to that of the pump laser and the absorption offset relative to the CO₂ center frequency. The assignment of the rotovibrational states for the pump and the emission transitions of ethyl bromide are calculated. We also partly assigned the rotational levels of trioxane.     

Third-order optical nonlinearities of Zn1-xMgxO thin films

The Zn1-xMgxO thin films were deposited on sapphire substrates by reactive electron beam evaporation deposition (REBED). The X-ray diffraction (XRD) measurement demonstrates that these films undergo phase transition from hexagonal to cubic with increasing the Mg concentration. Absorption coefficients at 532 nm of the samples were obtained from the absorption spectra. Using optical Kerr effect, the thirdorder susceptibilities of the ternary films over a wide range of Mg concentrations were determined. The magnitude of x(3) of the ternary Zn1-xMgxO films is order of 10-11 esu at λ = 532 nm. The sample with phase mixture of both hexagonal and cubic structures shows the largest third-order susceptibility. The difference observed in the magnitude of x(3) of Zn1-xMgxO films is attributed to the different microstructures of the ternary films, such as crystalline phase separation and crystal grains that enhance stimulated scattering.     

管范畴上的算子及其应用

本文定义了管范畴上的一些算子,研究了它们的一些性质,给出了循环单列代数的Ringel-Hall代数H(T)的结构常数FML,N的一个计算公式．利用这些算子和这个公式,我们得到了其合成代数C(T)及半单模[l(?)i=1nSi](t∈Z+)在H(T)中的一些中心化子．事实上,它们是H(T)的中心元素,且是H(T)在其合成代数C(T)上代数无关的生成元．     

Self-catalytic synthesis and light-emitting property of highly aligned Mn-doped Zn2SiO4 nanorods

Highly aligned Mn-doped Zn₂SiO₄ nanorods were fabricated by using a modified vapor-phase evaporation method. Their microstructure and chemical bond configurations were investigated with the help of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared absorption spectroscopy, and X-ray photoelectron spectroscopy. The formation process of the Mn-doped Zn₂SiO₄ nanorods can be elucidated on the basis of a self-catalytic vapor–liquid–solid growth mechanism in which Mn chloride hydrate acts as the catalyst and impurity source. Photoluminescence measurements revealed that an intensive green luminescence peak appears at 523 nm, which corresponds to the electronic transition ⁴T₁(⁴G)→⁶A₁(⁶S) of Mn²⁺ ions. Our experimental results provide a useful approach to directly fabricate Si-based nanoscale light-emitting materials using ZnO–Zn₂SiO₄ composite. PACS 81.05.-t; 81.10.Bk; 81.07.-b     

Impulsive loading of clamped monolithic and sandwich beams over a central patch

An analytical model is developed for the response of clamped monolithic and sandwich beams subjected to impulse loading over a central loading patch. A number of topologies of sandwich core are investigated, including the honeycomb core, pyramidal core, prismatic diamond core and metal foam. The various cores are characterised by their dependencies of through-thickness compressive strength and longitudinal tensile strength upon relative density. Closed-form expressions are derived for the deflection of the beam when the ratio r of length of loading patch to the beam span exceeds 0.5. In contrast, an ordinary differential equation needs to be solved numerically for the choice r<0.5. Explicit finite element calculations show that most practical shock loadings can be treated as impulsive and the accuracy of the impulsive analytical predictions is confirmed. The analytical formulae are employed to determine optimal geometries of the sandwich beams that maximise the shock resistance of the beams for a given mass. The optimisation reveals that sandwich beams have a superior shock resistance relative to monolithic beams of the same mass, with the prismatic diamond core sandwich beam providing the best performance. Further, the optimal sandwich beam designs are only mildly sensitive to the length of the loading patch.