Schur-Convex Functions and Isoperimetric Inequalities

In this paper, we establish some analytic inequalities for Schur-convex functions that are made of solutions of a second order nonlinear differential equation. We apply these analytic inequalities to obtain some geometric inequalities.

     

Pleiocarpumlignan A,a new dineolignan from Piper pleiocarpum Chang ex Tseng

Abstract

The investigation of chemical constituents from the whole plants Piper pleiocarpum Chang ex Tseng resulted in the isolation of one new dineolignan, pleiocarpumlignan A (1), along with one known benzoate derivative, trans-2,3-diacetoxy-1-[(benzoy1oxy)methyl]-cyclohexa-4,6-diene (2), and two known neolignans (3–4) as (±)-trans-dehydrodiisoeugenol (3), (7R,8R,3′S)-△^8′-3′,6′-dihydro-3′-methoxy-3,4-methylenedioxy-6′-oxo-8,3′,7,O,4′-lignan (4). Their structures were elucidated through extensive spectroscopic analyses including 1D, 2D NMR, HR-ESI-MS, and by comparison with the literature. All compounds (1–4) were firstly isolated from Piper pleiocarpum Chang ex Tseng. The ¹³C NMR spectra of 2 were completely assigned for the first time. Cytotoxic activities of these isolated compounds against five human cancer cell lines (including A-549, SMMC-7721, HL-60, MCF-7, and SW-480) were evaluated.     

Dynamic Geometry of Polygons

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Dynamic Geometry of Polygons

     

第三讲宇宙中的暗物质和暗能量

文章对暗物质粒子的候选者和宇宙中暗能量的研究现状作一简单介绍．     

Detecting dark energy in long baseline neutrino oscillations

In this paper, we discuss a possibility of studying properties of dark energy in long baseline neutrino oscillation experiments. We consider two types of models of neutrino dark energy. For one type of models the scalar field is taken to be quintessence-like and for the other phantom-like. In these models the scalar fields couple to the neutrinos to give rise to spatially varying neutrino masses. We will show that the two types of models predict different behaviors of the spatial variation of the neutrino masses inside the Earth and consequently result in different signals in long baseline neutrino oscillation experiments.     

Hydrogen bonded framework structures constructed from 2-(pyridyl N-oxide) methylphosphonic acid ligands and erbium(III)

Syntheses for 2-(pyridyl N-oxide) methylphosphonic acid, 1-H, and 2-(pyridyl N-oxide) hydroxymethylphosphonic acid, 4-H, are described, and the crystal structures of both ligands are presented. Combination of these ligands with freshly prepared erbium hydroxide results in the formation of the isostructural complexes Er(L(-))(3)(LH).8H(2)O. The crystal structure determinations of the complexes show that extensive hydrogen bonding links the individual eight coordinate Er(L(-))(3)(LH) molecular units into a 3-D structure.     

Er,Yb:YAG微晶玻璃发光特性的研究

高温熔制Er³⁺，Yb³⁺离子掺杂CaO-Y₂O₃-Al₂O₃-SiO₂系统玻璃，并进行微晶化处理，研究了微晶玻璃中Er³⁺离子的发光及上转换发光特性，分析了微晶玻璃上转换发光机理.结果表明：原始玻璃经热处理得到了Er,Yb:YAG微晶玻璃，微晶玻璃中Er³⁺离子在室温下⁴I_13/2→⁴I_15/2跃迁产生横盖1450—1650nm区间的超宽带荧光，荧光半高宽达180nm，这可能由于YAG微晶相中Er³⁺离子与玻璃相中残留Er³⁺离子的共同发光；Er³⁺与Yb³⁺离子局域基质声子能量的降低使微晶玻璃Er³⁺离子上转换发光强度与原始玻璃相比显著提高，绿光、红光上转换荧光强度比玻璃样品分别增强约7和3倍；微晶化后Er³⁺，Yb³⁺离子局域环境发生变化也导致微晶玻璃中Er³⁺离子绿光、红光上转换发光相对强度发生变化. 关键词： 铒 镱:钇铝石榴石 微晶玻璃 荧光光谱     

生物荧光氧化硅纳米颗粒的研制与应用

运用OP-10(壬基酚聚氧乙烯醚)/环己烷/氨水微乳液自组装体系合成了罗丹明B嵌入的荧光氧化硅纳米颗粒.通过电镜检测、光谱分析以及荧光猝灭试验研究了荧光颗粒的特性.将荧光纳米颗粒与培养细胞共培育后,通过激光扫描共聚焦显微镜和流式细胞仪研究了不同时间点细胞内荧光信号和荧光强度.结果表明,合成的荧光氧化硅纳米颗粒粒径小（约20 nm）,分布均匀,形态规则,表面光滑圆润,发光性质稳定.它可被体外培养细胞有效摄入,并可在培养细胞中检测到较强的荧光信号和较高的荧光强度.这提示生物荧光氧化硅纳米颗粒在细胞生物学、超微化学与免疫检测等领域将具有重要应用前景.     

甲烷二氧化碳转化制备富含一氧化碳合成气

研究了甲烷二氧化碳转化反应的热力学特性,计算了反应平衡常数及平衡组成,分析和确定了抑制积碳的生成条件,采用固定床流动和脉冲反应装置研究了Ni/Al_2O_3催化剂对甲烷二氧化碳转化的催化性能。     

N-Myristoylated Phosphatidylethanolamine: Interfacial Behavior and Interaction with Cholesterol

The interfacial packing behavior of N-myristoyldimyristoylphosphatidylethanolamine (N-14:0 DMPE) and its interaction with cholesterol were characterized and compared to the behavior of dimyristoylphosphatidylethanolamine (DMPE) using an automated Langmuir type film balance. Surface pressure and surface potential were monitored as a function of lipid cross-sectional molecular area. N-14:0 DMPE exhibited two-dimensional (2D) phase transitions of a liquid-expanded to condensed nature at many temperatures in the 15-30 °C range, but isotherms showed only condensed behavior at 15 °C. The sharp decline in the surface compressional moduli upon entering the 2D-transition region is consistent with differences in the partial molar areas of coexisting liquid-expanded (chain-disordered) and condensed (chain-ordered) phases. Including Ca(2+) in the subphase beneath the negatively charged N-14:0 DMPE caused a downward shift in the 2D-transition onset pressure even in the presence of 100 mM NaCl. The average dipole moments perpendicular to the lipid-water interface for N-14:0 DMPE's liquid-expanded and condensed phases were higher than those of DMPE. At surface pressures sufficiently low (<10 mN/m) to produce liquid-expanded phase behavior in pure N-14:0 DMPE, mixing with cholesterol resulted in a classic "condensing effect". Maximal area condensation was observed near equimolar N-14:0 DMPE/cholesterol. Insights into mixing behavior at high surface pressures that mimic the lipid cross-sectional areas of biomembranes were provided by analyzing the surface compressional moduli as a function of cholesterol mole fraction. Complex mixing patterns were observed that deviated significantly from theoretical ideal mixing behavior suggesting the presence of lipid "complexes" and/or a liquid-ordered phase at high sterol mole fractions (>0.35) and low to intermediate surface pressures (<20 mN/m) as well as the possible coexistence of relatively immiscible solid phases at higher surface pressures (e.g., 35 mN/m).