水上桩基试验与成果分析

结合某大型港口项目的工程实例,利用静载试验、动载试验、应变测试的原理和方法,根据现场的地质条件,在试桩桩身的相应位置安装电阻应变片,沉桩过程中进行动载初打试验,经过一定的休止时间,再进行动载复打试验;然后搭设水上试验工作平台,进行静载试验,并同时进行应变测试.三种试验手段综合应用,互为补充,为确定主码头桩长和调整桩尖结构型武提供了科学依据,并解决了密实粉土层的沉桩可行性问题.试验成果弥补了该区域试桩资料的空白,为进一步开展桩-土相互作用的研究提供了可以借鉴的参数.     

TNF-α、IL-6、IL-8在Modic I型改变腰椎终板与椎间盘髓核中的表达及关系研究

目的 探讨腰椎Modic I型改变的腰椎终板与椎间盘髓核中TNF-α、IL-6、IL-8 的相关性。方法 收集30 例因下腰痛入院手术治疗并行腰椎MRI 检查确认为腰椎Modic I型改变患者的术中病灶椎间盘标本,进行免疫组化检测,并观察椎间盘组织病理变化及炎症因子的表达,IL-6、IL-8 相对表达水平以相对表达量△Ct 或（2-△Ct×104）进行分析。结果 Modic I型终板中TNF-α表达水平（9.2±0.7）高于髓核（7.2±0.5）,差异有统计学意义（P＜0.05）;髓核中△Ct IL-6、△Ct IL-8 相对表达量（6.34±1.82、10.62±1.88）高于终板（4.07±1.86、5.92±1.31）,差异均有统计学意义（均P＜0.05）。结论 Modic I型终板中TNF-α、IL-6、IL-8的表达水平明显高于髓核,其引起下腰痛的原因主要为终板的炎症改变。     

Preparation of Fluorescent Polystyrene via ATRP with Dimethylamino Chalcones as Initiator

4‐(3‐(4‐(Dimethylamino)phenyl)acryloyl)phenyl‐2‐bromo‐2‐methylpropanoate (APPBr) was used for the heterogeneous atom transfer radical polymerization (ATRP) of styrene (St) with copper(I) bromide/N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA) catalytic system. The functional end group was characterized via UV‐Vis and ¹H NMR spectra. The polymerization showed a first‐order kinetic characteristic and each of the obtained polymers had well‐controlled molecular weight and relatively low polydispersity index (PDI). Furthermore, the obtained end‐functionalized polystyrene (PS) in solution showed strong green‐light emission which is further affected by mixing different metal cations. In particular, the fluorescent intensity of the polymer was decreased in the presence of Ag⁺, Cu²⁺ and Fe³⁺.     

Fabrication of Melamine/Tb3+-Intercalated Polydiacetylene Nanosheets and Their Thermochromic Reversibility

Polydiacetylene (PDA) is one kind of the conjugated polymer with layered structure, which can serve as a host to accommodate the guest components through intercalation. In these intercalated PDAs, some of them were reported to have a nearly perfect organized structure and perform completely reversible thermochromism. Till now, these reported intercalated PDAs were made by only introducing a single component for intercalation. Here, we chose 10, 12-pentacosadiynoic acid (PCDA) as the monomer, of which the carboxyl-terminal groups can interact with either Tb\begin{document}$ ^{3+} $\end{document} ions or melamines (MAs). When the feeding molar ratio of PCDA, MA, and Tb\begin{document}$ ^{3+} $\end{document} ion was 3:267:1, only Tb\begin{document}$ ^{3+} $\end{document} ions were intercalated though excess MAs existed. Such Tb\begin{document}$ ^{3+} $\end{document}-intercalated poly-PCDA exhibited completely reversible thermochromism, where almost all the carboxyl groups interacted with Tb\begin{document}$ ^{3+} $\end{document} ions to form the nearly perfect structure. When the feeding molar ratio of PCDA, MA, and Tb\begin{document}$ ^{3+} $\end{document} ion was 3:267:0.6, both Tb\begin{document}$ ^{3+} $\end{document} ions and MAs were intercalated. There existed some defects in the imperfect MA-intercalated domains and at the domain boundaries. The MA/Tb\begin{document}$ ^{3+} $\end{document}-intercalated poly-PCDA exhibits partially reversible thermochromism, where the backbones near the defects are hard to return the initial conformation, while the rest, those at nearly perfect organized domains, are still able to restore the initial conformation.     

Association behavior of linear ω-functionalized polybutadienes in cyclohexane

The dilute solution properties of linear polybutadienes with dimethylamine and zwitterionic end groups were studied by membrane osmometry (MO), low-angle laser light scattering (LALLS), viscometry, and dynamic light scattering (DLS) in cyclohexane. The polymers were prepared by anionic polymerization, under high vacuum conditions using [3-(dimethylamino)propyl]lithium as initiator. The dimethylamine groups were converted to zwitterions by reaction with cyclopropane sultone. No evidence of association was found for the amine-capped polymers, whereas the zwitterionic samples exhibited strong association in cyclohexane. The degrees of association increase by decreasing molecular weight of the base polymer due to the excluded volume repulsions. These aggregation numbers are of the same order as those found for ω-functionalized polyisoprenes, with the same polar groups in the same solvent. The hydrodynamic properties, measured by viscometry and dynamic light scattering, supported the conclusions drawn by LALLS and provide strong evidence that the aggregates behave hydrodynamically as star polymers. Comparison with theoretical models shows that the association behavior is best described by the linear head packing model. © 1996 John Wiley & Sons, Inc.     

葛根黄酮对糖基化终产物致细胞损伤的修复

研究了糖基化终产物（AGEs）对血管内皮细胞（VEC）的作用,以及葛根黄酮对AGEs致VEC损伤的修复.以体外培养的新生小牛胸主动脉VEC为材料,检测了AGEs (4 g/L)作用于VEC 24 h后,细胞内一氧化氮（NO^-₂/ NO^-₃）、丙二醛(MDA)、谷胱甘肽（GSH）和脂褐素（LPF）含量的变化;细胞乳酸脱氢酶（LDH）的泄漏量;AGEs对细胞生长增殖的影响,及细胞形态和超微结构的变化.结果显示AGEs (4g/L)可使细胞增殖率、LDH、MDA及LPF含量显著升高（P<0.01）,NO^-₂/ NO^-₃和GSH含量显著降低(P<0.01).细胞形态收缩变形,胞内出现脂滴和空泡.同时加入葛根黄酮,可使以上指标及细胞形态均接近或恢复到正常水平.因此,葛根黄酮可作为防治糖尿病血管并发症的外源性氧自由基清除剂.     

塑料光纤纤端光场测试结果及分析

对纤端光场进行了理论分析,分别利用塑料光纤和多模光纤作为接收光纤对塑料光纤的出射纤端光场进行了测量,并与理论分析结果进行了比较,给出了合理的调和参数.传输距离较长的塑料光纤由于高阶模的泄漏,纤端光场分布非常接近高斯分布.实验结果表明了理论分析结果和调和参数选择的合理性.     

Characterization of the Phytochemical Composition and Bioactivities of Anacyclus maroccanus Ball. and Anacyclus radiatus Loisel Aerial Parts: Preliminary Evidence for the Possible Development of Moroccan Plants

In the present study, the phytochemical composition and bioactivities of A. maroccanus (AM) and A. radiatus (AR), two ecotypes collected in the Demnate road and Essaouira regions, respectively, were studied to highlight a pharmacological interest and to enable possible pharmaceutical development. To this end, methanolic and ethyl acetate extracts were prepared for each ecotype by fractionation; next, their phytochemical composition was evaluated by spectrophotometric and chromatographic analysis. Moreover, in line with the available evidence for Anacyclus spp. and their traditional use, a screening of bioactivities, including antioxidant, hypoglycemic, antiglycative, chelating, and antibacterial activities, was performed. The extracts were characterized by high amounts of polyphenols, tannins, and flavonoids, especially in the methanolic extracts; these samples were also enriched in carotenoids despite a lower chlorophyll content. Chlorogenic acid and rutin were the major identified compounds. The extracts also showed interesting hypoglycemic, antiglycative, and antibacterial properties, although with differences in efficacy and potency. Present results provide more scientific basis to the ethnopharmacological uses of Anacyclus spp. and suggest a further interest in AM and AR ecotypes as natural sources of bioactive compounds and/or phytocomplexes for possible pharmaceutical and nutraceutical developments.     

黏弹性接触界面端附近的奇异应力场

研究蠕变加载条件下线黏弹性材料接触界面端附近的奇异应力场问题.考虑接触界面的摩擦,假设界面端的滑移方向不改变,相对滑移量微小,且其与位移同量级,由此线性化局部边界条件,根据对应原理得到Laplace变换域中的界面端应力场,导出时域中奇异应力场的卷积积分表达式.对卷积积分核函数进行数值反演,考虑接触材料的两类组合,一是持久模量具有量级上的差异,另一是持久模量接近相同.算例结果证实核函数可以用准弹性法求得的解析式较准确地近似.在此基础上,利用积分中值定理,并引入各应力分量的修正系数,得到黏弹性奇异应力场的简化式.结合核函数的数值反演结果分析修正系数表达式的取值范围,得到如下结论,若两相接触材料的持久模量相差很大,可以采用准弹性解的解析式较准确地描述界面端的奇异应力场;一般情况下,应力场不存在统一的奇异值和应力强度系数,当采用类似于准弹性解的表达式近似给出黏弹性应力场时,可以估计此近似描述的误差限.文中最后采用有限元分析黏弹性板端部嵌入部位的应力场,算例包括了黏弹性板与弹性金属支承、黏弹性板与黏弹性垫层所形成的滑移接触界面端,利用黏弹性有限元的数值结果验证理论分析所得结论的有效性.      

树枝状嵌段聚合物D-PCL-b-PS在不对称末端受限条件下的结晶行为

研究了树枝状嵌段聚合物聚(ε-b-己内酯)-b-聚苯乙烯(D-PCL-b-PS)的分子结构对PCL链段受限结晶行为的影响.首先,通过活性正离子开环聚合(ROP)合成了树枝状的嵌段聚合物D-PCL.在此基础上用原子转移自由基聚合(ATRP)的方法,合成了树枝状的嵌段聚合物D-PCL-b-PS,在结晶的PCL链段的两个末端...