多室正交异性板箱形梁桥剪滞的半解析法

将带有纵向加劲肋的多室梯形箱形梁桥作为正交异性板折板结构考虑,采用艾瑞应力函数法给出了平面应力状态时正交异性板一般边界条件下的二维应力及位移的解析表达式一般形式。然后根据板梁在二者连接处的纵向线应变与侧向曲率两个形变协调条件解出了多室正交异性板箱形梁桥的应力分布与剪力滞后的半解析公式,使用时采用类似于有限条法的步骤计算,但输入数据和运算时间却很少。该方法兼有解析法精确条理与数值法方便灵活的特点,可推广应用于高层筒体结构和带有曲线预应力钢索的箱形梁桥等。     

Structural ordering in glass forming tellurium-germanium melts

The character of reorganization of the short-range order and the scale structure during the ordering of glass forming melts is elaborated based on the results of diffraction and microscopic investigations of the ordered and glassy alloys in tellurium-germanium systems. For this purpose cooling curves reflecting the formation processes of structural levels in real time are analyzed and the effective activation energies are estimated.     

Complexes of lysozyme with sodium (sulfamate‐carboxylate)isoprene/ethylene oxide double hydrophilic block copolymers

Complexes between sodium (sulfamate‐carboxylate)isoprene/ethylene oxide double hydrophilic block copolymers and lysozyme, a globular protein, were formed in aqueous solutions, at pH 7, because of electrostatic interactions between the anionic groups of the polyelectrolyte block of the copolymers and the cationic groups of lysozyme. The structure of the complexes was investigated as a function of the anionic/cationic charge ratio of the two components in solution and ionic strength by static, dynamic, and electrophoretic light scattering, atomic force microscopy, and fluorescence spectroscopy. The mass and size of the micellar‐like complexes depend on the mixing ratio and the molecular characteristics (molecular weight, composition, and architecture) of the copolymer used. Complexation persists at 0.15M NaCl, the value for physiological saline, as a result of additional hydrophobic interactions between the copolymers and the enzyme. Fluorescence spectroscopy measurements indicate that the secondary structure of lysozyme does not change substantially after complex formation. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 509–520, 2007     

Algorithms for generalized halfspace range searching and other intersection searching problems

In a generalized intersection searching problem, a set S of colored geometric objects is to be preprocessed so that, given a query object q, the distinct colors of the objects of S that are intersected by q can be reported or counted efficiently. These problems generalize the well-studied standard intersection searching problems and have many applications. Unfortunately, the solutions known for the standard problems do not yield efficient solutions to the generalized problems. Recently, efficient solutions have been given for generalized problems where the input and query objects are iso-oriented (i.e., axes-parallel) or where the color classes satisfy additional properties (e.g., connectedness). In this paper, efficient algorithms are given for several generalized problems involving objects that are not necessarily iso-oriented. These problems include: generalized halfspace range searching in , for any fixed d ≥ 2, and segment intersection searching, triangle stabbing, and triangle range searching in for certain classes of line segments and triangles. The techniques used include: computing suitable sparse representations of the input, persistent data structures, and filtering search.     

Determination of structural parameters from EXAFS: Application to solutions and catalysts

Summary A review is presented of applications of extended X-ray absorption fine-structure (EXAFS) spectroscopy to the determination of structural detail in inorganic solutions and supported metal catalyst particles. Similarities in these applications are noted and the possible role of disorder on the reliability of the EXAFS results is discussed. A brief summary of data analysis procedures is presented with examples. Paper presented at the Workshop on ?EXAFS Data Analysis in Disordered Systems?, held in Parma, October 5–7, 1981.     

Resonant magnetopolaron effects in GaAs/AlGaAs multiple quantum well structures

A detailed experimental study of electron cyclotron resonance (CR) has been carried out at 4.2 K in three modulation-doped GaAs/Al_0.3Ga_0.7As multiple quantum well samples in fields up to 30 T. A strong avoided-level-crossing splitting of the CR energies due to resonant magnetopolaron effects is observed for all samples near the GaAs reststrahlen region. Resonant splittings in the region of AlAs-like interface phonon modes of the barriers are observed in two samples with narrower well width and smaller doping concentration. The interaction between electrons and the AlAs interface optical phonon modes has been calculated for our specific sample structures in the framework of the memory-function formalism. The calculated results are in good agreement with the experimental results, which confirms our assignment of the observed splitting near the AlAs-like phonon region is due to the resonant magnetopolaron interaction of electrons in the wells with AlAs-like interface phonons.     

On the structure of alkali halide solutions

Summary The adiabatic compressibility of NaCl, NaBr and NaI water solutions has been determined by measuring the sound velocity as a function of both concentration and temperature. A simple model has been employed to interpret the data in terms of size of hydration shells. Reasonably good agreement has been found with neutron and X-ray diffraction results.

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Riassunto La compressibilità adiabatica delle soluzioni acquose di NaCl, NaBr ed NaI è stata misurata determinando la velocità del suono in funzione di temperatura e concentrazione. Per interpretare i dati è stato impiegato un modello semplice che tiene conto delle sfere di idratazione degli ioni. Tale modello risulta in soddisfacente accordo con i dati ricavati da un esperimento di diffrazione di raggi X e neutroni.

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Резюме Определяется адиабатическая сжимаемость водньх растворов NaCl, NaBr и NaI, используя измерения зависимостей скорости звука от концентрации и температурь. Предлагается простая модель для интерпретации данньих в терминах размера сферьі гидратации. Получется хошее согласие с результатами дифракции нейтронов и рентгеновских лучей.

     

Thermal neutron polarisation

The basic principle for the production of polarised thermal neutrons is discussed and the choice of various crystal monochromators surveyed. Brief mention of broad-spectrum polarisers is made. The application of polarised neutrons to the study of magnetisation density distributions in magnetic crystals, the dynamic concept of polarisation, principle and use of polarisation analysis, the neutron spin-echo technique are discussed.     

Resonance condition for asymmetrical triple-barrier structures

The resonance condition for triple-barrier structures with arbitrary potential is studied systematically. The quasisymmetrical triple-barrier (QST) resonance mode and the quasi-asymmetrical double-barrier (QAD) resonance mode may both exist in asymmetric triple-barrier structures. The QST consists of two submodes: a normal mode (doublet) and a degenerate mode (singlet). The critical condition for distinguishing the two modes is examined. It is confirmed that there are both unity resonant transmission and below-unit resonant transmission in the asymmetrical triple-barrier structure. Furthermore, the wavefunctions of an electron at resonance level are calculated and the confining phenomenon is studied.     

Implementing the ALGOL 68 heap

The implications of the heap, reference variables and global generators in ALGOL 68 are examined and some notes on possible implementation mechanisms are presented. In particular the use or simulation of hardware with segment addressing facilities is discussed.