Polar functions and intersections of the random string processes

Let {us(x) : s ≥ 0 , x ∈R} be a random string taking values in Rd . The main goal of this paper is to discuss the characteristics of the polar functions of {u s(x) : s ≥ 0 , x∈R} . The relationship between a class of continuous functions satisfying the H¨older condition and a class of polar-functions of {us (x) : s ≥ 0 , x ∈R} is presented. The Hausdorff and packing dimensions of the set that the string intersects a given non-polar continuous function are determined. The upper and lower bounds are obtained for the probability that the string intersects a given function in terms of respectively Hausdorff measure and capacity.     

Interaction-Induced Chiral Quantum States of the Ultracold Polar Molecules

The ultracold polar molecules with the tunable dipole-dipole interaction, not only would enable explorations of a large class of exotic many-body physics phenomena, but also could be used for quantum information processing. In the present paper we demonstrate that this dipole-dipole interaction can generate the degenerate chiral quantum states acting as a qubit robust against noise when the ultracold polar molecules are confined by a triangular lattice. Moreover, we also find two first-order quantum phase transitions by controlling an external driving field. One is the transition with the change of the different degenerate chiral quantum states. The other is the transition with the breaking of the degenerate quantum chiral states to the nondegenerate state. In experiment, these first-order quantum phase transitions can be detected by measuring the collective molecular population.     

Inelastic light scattering studies of diffuse phase transition in ferroelectric Sr1.9Ca0.1NaNb5O15 thin films

The dynamic behavior of highly oriented ferroelectric Sr_1.9Ca_0.1NaNb₅O₁₅ thin films has been investigated by Brillouin light scattering over a wide temperature range between 25 and 450 °C. The temperature variations of the full‐width at half‐maximum (FWHM) of the central peak (CP) are found to exhibit marked changes around the Curie temperature (T_c = 246 °C). The CP reveals a relaxational mode behavior, which is attributed to thermally activated fast relaxation of polar nanoregions (PNRs). The width of the CP decreases steadily upon cooling from ∼400 °C to T_c and shows little subsequent change within the ferroelectric state, indicating an increase of the number of PNRs and a slowing down of their dynamics. By using a modified superparaelectric model, the activation energy (H₀) of the relaxation processes and the Burns temperature (T_B) are determined to be 2939 and 385 °C, respectively. The evidence for this diffuse phase transition provided by Brillouin scattering is in agreement with results obtained from the temperature‐dependent dielectric permittivity, refractive index, and Raman spectra. Copyright © 2011 John Wiley & Sons, Ltd.     

La3ScBi5的合成与晶体结构

在氩气保护下，将金属单质置于钽管中进行高温固相反应得到了一个新的三元极性金属间化合物,La₃ScBi₅。通过X-射线单晶衍射确定了它的晶体结构。La₃ScBi₅晶体属六方晶系，空间群为P6₃/mcm(No.193)，晶胞参数为：a=b=0.975 73(5) nm，c=0.655 92(6) nm，V=0.543 41(9) nm³，Z=2。La₃ScBi₅属反式Hf₅Sn₃Cu结构类型，其结构特征为Bi的一维直线链和由ScBi₆八面体之间通过共面形成的{ScBi₃}链。能带计算表明La₃ScBi₅呈金属导电性。     

Selective polarity- and adsorption-guided extraction/purification ofAnnona sp. Polar acetogenins and biological assay against agricultural pests

Annonaceae acetogenins (AG) comprise a family of natural chemical modifications of long-chain fatty acids (C₃₅_₃₇) bearing one to several hydroxyls (less often oxo), middle-chain tetrahydrofuran rings, and a γ-lactonized, α/β-unsaturated carboxyl group. Acetogenins’ strong biological activity as larvicides, pesticides, and antitumorals is dependent on these structural variations. The hydroxylation degree is particularly important for these etfects. Seeds, albeit rich in fats (mostly triacylglycerols, [TAG]), are a nonpredatory source of these drugs as compared to other botanical parts such as roots and stems. Conventional lipid extractions lead to quantitative lipid recovery and then the unfavorable natural ratio of TAG:AG in the range >90:<0.1 These extracts thus require, for instance, partitions and extensive sílica gel column chromatographic steps, in order to enrich or purify the AG fraction(s). Great operational difficulties result from the similar polarity and mol. wt. range of TAG and AG when carrying out these purification steps. An alternative fast two-step procedure to obtain polar acetogenin (pAG)-enriched preparations was developed. The extraction procedure forAnnona spp. seeds pAG was carried out with acetonitrile (Eβ = 0.65; log P = - 0.33) as a polar organo-solvent, followed by the adsorption of the solvent-free extract on activated charcoal, then washed with hexane and/or chloroform (Eβ = 0.0 and 0.40: log P = 3.5 and 2.0) for most of the contaminating TAG removal, and then with acetone (Eβ = 0.56; log P = - 0.23) to the desorption of an enrichedpAG fraction. An alternative procedure for pAG extraction was supercritical fluid extraction (SFE) at moderate thermopressurization conditions (65-82βC; 120-130 atm) using CO2, with 10% acetonitrile as the polarity modifier. The pAG fractions’ bioactivity was evaluated with the brine-shrimp test (BST), and for feed deterrance, growth inhibition, and lethality against the high-impact agricultural pestsAnticarsia gemmatalis andPseudaletia sequax caterpillars feeding on soya or grass leaves sprayed with a 10% alcohol-stabilized emulsion of pAG.     

二维凝聚体系中分子的取向分布函数性质

对二阶和四阶Legondre多项式构造的取向分布函数进行了仔细研究, 发现该函数适于描述二维凝聚体系中单轴取向分子的四种分布模式, 给出了这四种分布模式对应的序参数〈P_2〉,〈P_4〉的取值区域, 具体讨论了序参数〈P_2〉,〈P_4〉改变时, 分布图形的相应变化.     

Sulpholane--A new solvent for the Baylis-Hillman reaction

Sulpholane, a commercially available solvent, is used for the first time as a new solvent for the Baylis-Hillman reaction under ambient conditions; a wide variety of olefins as well as aldehydes participate very efficiently resulting in good to excellent yields of products. Acrylamide also underwent the Baylis-Hillman reaction with 4-nitrobenzaldehyde under these reaction conditions.     

极地平流层云及其非均相化学

南极臭氧洞的形成与南极平流层云及其非均相化学过程有很大关系.南极平流层云中存在着硫酸气溶胶粒子、与硫酸/硝酸/水有关的固体或液体粒子以及水的冰晶粒子等,在其表面上可以发生非均相化学反应,一方面使本来比较惰性的硝酸氯(ClONO₂)具有相当大的活性,另一方面可以把NO₂或硝酸以硝酸固体粒子的形式从平流层中移走.由非均相化学产生的HOCl和Cl₂发生光离解,产生活性氯,加强了与ClO的二聚物或者与ClO-BrO互反应有关的破坏臭氧的催化循环圈的进行,加快南极臭氧洞的形成.本文重点介绍极地平流层云及其非均相化学在极地平流层臭氧消耗过程中的作用,使人们对加重平流层臭氧消耗的非均相化学有所了解。     

基于学科理解的“醛的结构与性质探究”教学设计与实施

学科理解是教师教学的坚实基础,教学设计环节首先进行学科理解研究,通过阐释“如何基于极性多重键认识羰基化合物的结构与性质？”本原性问题,对主题学科大概念“有机物构性关系”进行本原性、结构化地理解。从教学目标、教学思路、教学实施过程阐述“醛的结构与性质探究”一课的教学。课后阶段进行学生访谈及分析、专家评价和教师反思总结。系统地呈现基于学科理解的素养为本的课堂教学研究。