Studies on Synthesis of Two Novel Bowl-like Molecules and Their Fibrous Crystals

[中文文摘]以香兰素为原料,采用三聚法合成了2种外围脂肪族基团碳数分别为3和5的环三亚藜芦基(cyclotriveratrylene,CTV)系衍生物碗形分子——CTV-3和CTV-5,其中,用先关环后衍生化的合成路线克服了因CTV-5的外围基团太长、分子对称性不好而无法用传统方法合成的难题。产物的化学结构经1H NMR、13CNMR、质谱以及元素分析确认。在偏光显微镜下观察到纤维状晶叠加在碗形分子的向列液晶织构上。纤维状晶是从液晶态冷却时形成并装饰在原液晶织构上的一种结晶形态。通过SEM测定,观察到纤维状晶实际上是由厚度约为100～200nm、宽度为2～5μm的无限长的单层片晶组成的多层片晶,而片晶则是由直径约为100nm的微纤组成的。微纤可以推断是碗形分子柱的束状聚集体。[英文文摘]　Two novel bowl-like cyclotriveratrylene (CTV) ,i. e. CTV23 and CTV25 termed according to the different peripheral groups with carbon number 3 and 5 espectively,were synthesized. CTV23 was prepared by a the typical trimerization via a multistep sequence from vanillin ,however it remains restricted to the preparation of the CTV25 with larger peripheral group and less molecular symmetry via this conventional method. In this paper ,an alternative synthesis route with first closing ring and then derivatization was designed to prepare CTV25. The chemical structures of the products were characterized by means of 1H NMR ,13C NMR ,mass spectrometry and element analysis. For the final products CTV23 and CTV25 ,many fibrous crystals were observed under polarized optical microscopy ,which crystallized during the cooling from nematic phase ,and decorated the so-called liquid crystal grainy texture. By means of scanning electron microscope ,it can be observed the fibrous crystals were actually very long multi-layer lamellae ,which consist of single layer lamellae with the thickness of about 100 to 200nm ,width of 2 to 5μm and infinite length. The single layer lamellae were further composed of fibrils which diameter was about 100nm. It could be deduced that these fibrils were the aggregates of bowlic molecular columns国家自然科学基金项目(20774077); 福建省自然科学基金项目(E0510003); 厦门市科技计划项目(3502Z20055013)资助

用马赛克形貌装饰法研究碗形分子柱状向列相的向错和分子指向矢分布

选用香兰素为原料, 采用传统的三聚成环法, 合成了两种碗形CTV 系衍生物—— CTV-1 和CTV-2, 前者的外围基团是—OCH3 和—OCH2CH3, 后者的外围基团是—OCH3 和—OCH2COOCH3. 两种碗形CTV 分子均是热致液晶, 呈现向列相典型的粒状织构和单微区的均匀织构, 还观察到规则美观的马赛克形貌, 每块矩形马赛克的尺寸为数十微米数量级, 多次升降温循环能重复出现和消失. 发现马赛克形貌实质上是在冻结的向列相织构上结晶化并收缩龟裂而装饰出来的光学图案. 通过扫描电镜的研究, 观察到马赛克形貌是由片晶组装而成的, 每块马赛克就是一块矩形 的多层片晶, 多层片晶由单层片晶堆积而成. 直接观察到片晶的组成单元是直径约1 微米的微纤, 而微纤应当是束状的碗形分子柱. 马赛克形貌装饰在碗形分子柱状向列相上, 通过这种新方法观察到s = +1(δ = 0 和δ = 90°)和s = ±1/2 多种点向错和Nèel 微区壁等周围的分子指向矢分布情况. 说明碗形分子柱状向列相与一般向列相 有类似的液晶行为, 但取向的基本结构单元是碗形分子柱, 或者由碗形分子柱组成的束(即微纤), 而不是碗形分子本身. 碗形分子柱起了一般向列相中棒状分子的作用, 所以本文以一个新名称“碗形分子柱状向列相”BCN (Bowlic Columnar Nematic)来表示这种不同常规的向列相.国家自然科学基金基金(批准号:20774077); 福建省自然科学基金(E0510003); 厦门市科技计划项目（3502Z20055013)

含碗形CTV侧基的甲基丙烯酸酯类单体和聚合物

采用三聚法合成外围基团中含羟十一碳氧基的CTV衍生物(CTV-H),然后结合柱层析分离技术合成和分离出外围基团中含单甲基丙烯酸酯基团的CTV衍生物(CTV-M).以CTV-M为单体,本体聚合得到含碗形CTV侧基的甲基丙烯酸酯类聚合物(BPM).CTV-H和CTV-M都具有热致液晶性,是新的碗状液晶.SAXS和WAXD测定表明,液晶结构为六方柱相(Φh),柱直径为4.4 nm和4.8 nm,与理论计算结果相符.而BPM没有液晶性,呈非晶态

新型环三藜芦烃衍生物的合成及其热致液晶行为的研究

设计了先关环再衍生的方法,合成了系列外围含不同反应性官能团的新的环三藜芦烃(CTV)衍生物.利用1 H-NMR、13C-NMR、元素分析、质谱等对合成的CTV衍生物进行了结构表征.研究表明,分子间作用力增大会导致CTV衍生物的热致液晶性减弱,结晶性增强.合成的CTV-A具有热致液晶性;CTV-D和CTV-E由于氨基的存在产生了较强的分子间氢键作用,既形成了热致液晶态,又发生冷结晶;而CTV-B和CTV-C由于含有羧基、羰基、羟基或氨基等,分子间作用力强,只出现冷结晶,不能形成热致液晶.研究发现,通过外围基团的分子设计,调节氢键能力或柔性间隔基,可调节分子间作用力和熵的大小,从而控制CTV衍生物的热致液晶性

Scale Effects of China Mainland Coastline Based on Fractal Theory

以DEM为基础,并参照卫星影像,提取了不同比例尺下中国大陆海岸线,从海岸地质构造特征和海岸类型角度出发,对我国大陆海岸线整体、沉降隆起岸段和不同类型海岸尺度效应进行分析,并探讨了引起尺度效应差异的地理环境因素。研究表明:(1)中国大陆海岸线整体分形维数为1.195,岸线长度受测量尺度影响显著,定量刻画海岸线长度不可忽略相应测量尺度;(2)岸线分形受地质构造特征和水动力因素控制明显,隆起段和沉降段海岸线分形维数有着显著差异:辽东半岛隆起段分形维数为1.153,辽河—华北平原沉降段分形维数为1.116,山东半岛隆起段分形维数为1.148,苏北—杭州湾沉降段分形维数为1.177,浙东—桂南隆起段分形维数则达1.239;(3)海岸线尺度效应同时随海岸类型不同有着显著差异,位于冀北平原和滦河三角洲平原岸段的砂质岸线分形维数为1.109;位于苏北平原的淤泥质岸线分维数为1.056,位于闽东南山地丘陵的基岩海岸线分形维数达1.293。海岸线是陆、海和气界面的交汇线,其分形性质的定量刻画,可为多尺度研究海气、陆气和海陆相互作用提供科学基础。

A study on driving forces of land use change of Guangdong Province coastal zone and islands in recent 20a

在采用遥感和地理信息系统技术对1985年和2005年广东省海岛海岸带土地利用数据处理的基础上,对海岛海岸带土地利用变化及其驱动因子进行分析。分析表明:(1)各土地利用类型中,农用地面积变化最大,减少了2 048 km2,占研究区内1985年农用地总面积的31.4%;(2)研究区内共围填海370 km2,其中粤东、粤西和珠江口分别占12.6%,31.2%和56.2%;(3)珠海、广州、东莞、深圳、汕头和大亚湾等地城区面积扩张均在10倍以上,形成了环珠江口城市带;(4)近20 a来,研究区内整体土地利用综合变化率达24.2%,其中粤东、粤西和珠江口分别为15.6%,22.8%和28.2%。研究揭示了20 a间研究区内土地利用类型变化模式及其驱动力,为该区域土地资源规划、近岸海洋环境保护和深入研究奠定了基础,对其他海岸带及近海资源可持续利用具有借鉴意义。 &nbsp

纳微尺度镍粉的形貌调控及其电磁性能研究

<正>纳米镍(Ni)具有独特的物理和化学性质,在催化材料、吸波材料、高密度记录材料、磁流体、电池材料等领域具有广泛的应用。本文采用液相化学还原的方法,在90℃条件下,利用多元醇为溶剂,以水合肼为还原剂,以PVP为表面活性剂,制备了多种形貌的纳微尺度镍粉。采用X射

The Properties of Modified Nano-SiO_2/Acrylics Composite Coating

[中文文摘]丙烯酸酯是一类广泛应用的涂料品种,本文通过对纳米SiO2进行表面改性,利用共混法制备了一种纳米SiO2改性的丙烯酸酯复合涂料,然后实验考察了复合涂料的耐热性和耐磨性;结果发现,纳米复合材料的耐热性及耐磨性均有提高,并在3%(质量分数)含量时玻璃化转变温度(Tg)达到最高(147.8℃),耐磨性达到最佳;并结合扫描电镜(SEM)摩擦形貌的观察分析,对纳米粒子的提高材料耐磨性机理进行了初步探讨.[英文文摘]In this article,the surface of the nano-SiO2 was modified,and acrylics composite coating filled with the nano-SiO2 was prepared by blending method.The glass transition temperature(Tg) and the wear resistance of the composites were investigated.The results indicated that the Tg and wear resistance of the nano-composite rose,and the Tg of the composite coating was highest(147.8℃),and the wear resistance of the composite coating was best with 3% filled.The morphologies of the friction surface were observed and compared by SEM，and the wear mechanism was discussed.厦门市科技计划项目(3502Z20063004

Synthesis,Design and Liquid Crystal Behavior Characterization of a New Bowlic Liquid Crystal of CTV Derivative

[中文文摘]碗状的CTV(cyclotriveratrylene)系衍生物主要由三聚法合成,即以香兰素为原料,先制备所需结构的单体衍生物,再进行三聚关环的方法,但该方法无法合成具有较大外围基团的CTV衍生物.新设计了先关环后衍生化的合成路线,成功地合成了一种含较长脂肪链外围基团的新CTV衍生物-CTV-Ⅲ.产物的化学结构经1H-NMR1、3C-NMR、质谱以及元素分析表征验证.通过差示扫描量热法、热台偏光显微镜和小角激光光散射的研究表明,CTV-Ⅲ具有热致液晶性,在其液晶温区内呈现向列相,称为碗状液晶向列相(BN相).CTV-Ⅲ的升温相变序为:G 70℃Cr 87℃BN100℃I.[英文文摘]Normally the bowlic cyclot riverat rylene (CTV) derivatives were synthesized via a multistep sequence from vanillin. This typical method is termed trimerization. But it is difficult to prepare the CTV derivatives with large peripheral groups via this method.An alternative synthesis route ,i. e. derivation af ter ring closure reaction ,was designed to obtain the new CTV derivative2CTV2 Ⅲ. The chemical structure of the product was characterized by means of 1 H-NMR ,13 C-NMR ,mass spectrometry and element analysis. The behaviour of thermotropic liquid crystal of CTV-Ⅲ was observed by differential scanning calorimetry, hot stage coupled polarized optical microscopy and small angle laser light scattering. The mesophase of CTV-Ⅲ was nematic,named bowlic nematic phase (BN ). Its phase transition series of heating were determined to be G 70 ℃Cr 87 ℃BN 100 ℃ I.国家自然科学基金(20774077); 福建省自然科学基金(E0510003); 厦门市科技计划项目(3502Z20055013)

The Self-assemble Behavior of Benzoyl Chitosan and Amino Acids in Selective Solvents

[中文文摘]研究了苯甲酰化壳聚糖(DBC)和天然生物分子氨基酸在选择性溶剂N,N-二甲苯甲酰胺(DMF)和水中的自组装行为.在超声波作用下,透明的混合溶液出现蓝白色乳光,同时紫外-可见光谱呈现透光率的突变,体系完成了自组装.自组装是通过两组分之间的氢键作用产生的.用动态光散射(DLS)和透射电镜(TEM)分别研究了自组装粒子的尺寸和形态.实验结果表明,苯甲酰化壳聚糖和氨基酸可以形成纳米尺寸或亚微米尺寸的自组装微粒,形成的微粒为球形或椭球形,微粒的尺寸为60~720 nm.粒子的尺寸显著受pH值和氨基酸种类的影响,因而可以利用pH值和氨基酸的种类控制自组装粒子的尺寸.[英文文摘]Self-assemble of two kinds of natural biodegradable substances,i.e.benzoylchitosan and amino acids in selective solvents DMF and water was studied.Under ultrasonic treatment,mixed solution which is transparent gradually presented blue-white opalescence.At the same time,uv-vis spectra presented mutation of transmittance.The self-assemble of this system was finished.The behavior of self-assemble is induced by hydrogen bonding.The morphology and the size of the particles were characterized by dynamic light scattering (DLS) and t ransmission elect ron microscope ( TEM) . The results showed that benzoylchitosan and amino acids can self-assemble to form nanoparticles or submicron particles. The shape of the particles was spheroid or sphere ,the size of the particles was 60～720 nm. The size of the self2assembly particles can be influenced both by the p H of solution and the species of amino acids.Therefore ,we can adjust p H and the species of amino acids to control the size of self-assemble particles.国家自然科学基金(20774077); 福建省自然科学基金(E0510003); 厦门市科技计划项目(3502Z20055013)