介孔Worm-like孔壁晶化制备微孔-介孔分子筛研究

采用水热孔壁晶化法,以Worm-like介孔分子筛为硅源,十八水合硫酸铝为铝源,制备不同硅铝比微孔-介孔ZSM-5复合分子筛,XRD、FT-IR、N2吸附-脱附、TEM等表征结果证明,用此方法成功制备出一系列微孔-介孔ZSM-5复合分子筛.将一系列复合分子筛用于催化苯酚叔丁基化反应,在反应温度145℃、n(苯酚)∶n(叔丁醇)=1∶2.5条件下,硅铝比为15、25的复合分子筛有较强的催化活性,苯酚转化率和2,4-二叔丁基苯酚选择性分别超过90%和42%.

Worm-like分子筛负载磷钨酸催化剂的制备及光降解甲基橙的性能研究

以Worm-like分子筛为载体,采用浸渍法制备不同磷钨酸负载量的负载型催化剂,并采用傅里叶红外光谱(FT-IR)、X射线衍射(XRD)和N2吸附/脱附等手段对负载型磷钨酸催化剂进行表征。结果表明,磷钨酸成功负载在Worm-like分子筛上,且随着磷钨酸负载量的增加,FT-IR、XRD和N2吸附/脱附结果呈规律性变化。将该系列催化剂用于光催化降解甲基橙实验,结果表明,甲基橙质量浓度为20mg/L,磷钨酸负载量为70%(质量分数)时,甲基橙降解率为87.2%;回收催化剂并重复使用3次,甲基橙降解率仍达75%以上。

A simple method to synthesize worm-like AlN nanowires and its field emission studies

The worm-like AlN nanowires are fabricated by the plasma-enhanced chemical vapor deposition(PECVD)on Si substrates through using Al powder and N2 as precursors,CaF2 as fluxing medium,Au as catalyst,respectively.The as-grown worm-like AlN nanowires each have a polycrystalline and hexagonal wurtzite structure.Their diameters are about 300 nm,and the lengths are over 10μm.The growth mechanism of worm-like AlN nanowires is discussed.Hydrogen plasma plays a very important role in forming the polycrystalline structure and rough surfaces of worm-like AlN nanowires.The worm-like AlN nanowires exhibit an excellent field-emission(FE)property with a low turn-on field of 4.5 V/μm at a current density of 0.01 mA/cm^(2) and low threshold field of 9.9 V/μm at 1 mA/cm^(2).The emission current densities of worm-like AlN nanowires each have a good stability.The enhanced FE properties of worm-like AlN nanowires may be due to their polycrystalline and rough structure with nanosize and high aspect ratio.The excellent FE properties of worm-like AlN nanowires can be explained by a grain boundary conduction mechanism.The results demonstrate that the worm-like AlN nanowires prepared by the proposed simple and the PECVD method possesses the potential applications in photoelectric and field-emission devices.

Morphological stability of worm-like vesicles consisting of amphiphilic diblock copolymer against external stress

The morphological stability of vesicles consisting of an amphiphilic poly(methacrylic acid)- block-poly(methyl methacrylate-random-methacrylic acid) diblock copolymer, PMAA-b-P(MMA-r-MAA), was investigated against the external stresses of pH, salt concentration and polyamine. The worm-like vesicles underwent a partial fusion at pH 12, however, they retained the worm-like shape at pH 13 due to electrostatic repulsion. On the other hand, the spherical vesicles were completely fused at pH 12, transformed into a sheet and did not retain their shape under the higher basic condition. Similarly, the worm-like vesicles retained their morphology in 0.1 mol% solutions of sodium chloride and sodium dodecyl sulfate, while the spherical vesicles caused division and fusion even at much lower concentrations. Poly(2-dimethylaminoethyl methacrylate)(PDMAEMA) transformed the worm-like vesicle into a cleavable sheet, while it changed the spherical vesicles into a sheet without a specific form. It was found that this transformation based on the acid-base interaction between the carboxylic acid of the MAA block and the amine of the PDMAEMA was dependent on the molecular weight of the PDMAEMA. The short PDMAEMA retarded the fusion of the vesicles.

Worm-like micelles facilitate the intestinal mucus diffusion and drug accumulation for enhancing colorectal cancer therapy

Local delivery of nanoparticles holds promise for colorectal cancer(CRC)therapy.However,the presence of the mucus layer on the epithelium poses a significant challenge to drug delivery,thereby adversely affecting treatment efficiency.It is crucial to develop efficient drug delivery carriers that can effectively overcome mucus barriers to treat colorectal cancer.Herein,we utilized poly(1,4-butadiene)-b-poly(ethylene oxide)polymers to prepare four distinct geometries of polymeric micelles,namely linear micelles(LMs),worm-like micelles(WLMs),large spherical micelles(LSMs),and small spherical micelles(SSMs)to investigate the influence of shape effects on overcoming colonic mucosal barrier.We found that the carriers exhibited diverse shapes while maintaining comparable physicochemical properties.Of these,WLMs had an aspect ratio similar to segmented filamentous bacteria,which exhibited superior mucus penetration ability,leading to prolonged drug release kinetics and faster entry into epithelial cells compared to LSMs.Furthermore,rectally administrated 10-hydroxycamptothecin-loaded WLMs traversed the colorectal mucus in orthotopic CRC nude mice model,penetrated and accumulated within tumor tissue,and effectively aggregated within cancer cells,thereby inducing significantly robust antitumor outcomes in vivo.These findings underscore the significance of shape design in overcoming colonic mucosal absorption barriers,offering a novel approach for the development of drug delivery carriers tailored for effective tumor therapy.

Temperature-Induced Transformation from Large Compound Vesicles to Worm-like Aggregates by ABC Triblock Copolymer

Two triblock polymers, tetraaniline-block-poly（N-isopropyl acrylamide）-block-poly（hydroxyethyl acrylate） （TA-b-PNIPAM-b-PHEA） and TA-b-PHEA-b-PNIPAM, were synthesized with unambiguous structure by a two step method. The difference of these two diblock polymers is the connection order of carboxyl group to block, e.g., carboxyl group to PNIPAM block for PNIPAM-b-PHEA and to PHEA block for PHEA-b-PNIPAM. Secondly, block tetraaniline was linked to the diblock polymer through amidation to yield the corresponding triblock copolymer. Both of them have almost the identical chemical compositions. The only difference is the connection order of each block in the triblock polymers. When they were self-assembled at 45℃ in a suitable solution, both of their aggregates have spherical shape with slight defects on their surface with the average diameter of about 400 nm. However, when their aggregate dispersion was cooled down to 20 ℃, only TA-b-PHEA-b-PNIPAM＇s morphology changed, forming worm-like aggregates with the diameter of about 100-200 nm transformed from spherical ag- gregates. Both amphiphilic property and position of each block in this triblock copolymer are very essential for this morphology transformation. Since the worm-like aggregates presented here by our group have hollow structure in- side, its controlled release properties for doxorubicin were evaluated. Drug release experiment indicated that along with the temperature changes, the rearrangement of the intermediate layer structure caused morphology change in aggregate, thus accelerating the speed of drug release.

Fiber Bending Flexibility Evaluation by Worm-like Chain Model

A new method for characterizing fiber bending flexibility was developed by worm-like chain model proposed by Kratky-Porod,[1]which was first introduced to the pulp and paper field in this study.For the three types of pulps,the experimental results were compared with the KP chain model,and the resulting determination coefficients were all above 0.95,which proved that the model was feasible to be applied to these three fibers.The relation between fiber bending rigidity and that of cellulosic chains inside was discussed to deduce the fiber bending flexibility.The flexibility of an individual fiber can be approximated as the contribution of that of all the cellulose chains inside.By this method,the fiber flexibility values were determined to be in the range of 0.6×10^(11)-3.5×10^(11)N^(-1)·m^(-2),which was comparable to that of the conventional methods recorded in the literature.

金属离子Mn^(2+)对α-烯烃磺酸钠/月桂酰胺丙基羟磺基甜菜碱蠕虫状胶束形成的调控作用研究

Mn^(2+)可诱导阴离子表面活性剂α-烯烃磺酸钠(AOS)与两性离子表面活性剂月桂酰胺丙基羟磺基甜菜碱(LHSB)的混合物形成蠕虫状胶束。在表面活性剂质量分数1%~5%范围内,研究了AOS与LHSB质量比、Mn^(2+)质量分数、表面活性剂质量分数及温度对蠕虫状胶束黏弹性的影响。结果表明,随着AOS与LHSB质量比从1:9变为9:1以及Mn^(2+)质量分数的增加,表面活性剂溶液黏度先增大后减小。体系的零剪切黏度随表面活性剂质量分数指数增加。常温下研究了表面活性剂黏度的变化规律,测得AOS与LHSB质量比为3:7时体系黏度最大,且当表面活性剂质量分数为2%时的最佳Mn^(2+)含量为0.5%,此时零剪切黏度为9030.9 mPa·s。用冷冻透射电镜(cryo-TEM)观察胶束形态,发现此时溶液中蠕虫状胶束较长,网络结构紧密,呈现出良好的线性黏弹性。表面活性剂质量分数、Mn^(2+)质量分数对蠕虫状胶束的形成有较大影响。

Ca^(2+)介导的月桂酰甲基牛磺酸钠相行为研究

为探究高价无机盐对阴离子表面活性剂月桂酰甲基牛磺酸钠(SMLT)溶液的表面活性和相行为的影响,考察了Ca^(2+)浓度对SMLT溶液的表面张力和不同SMLT/Ca^(2+)摩尔比对SMLT/水二元体系的相行为影响。结果表明,加入适量的Ca^(2+)对其表面活性影响显著,当Ca^(2+)浓度从0增加至0.1 mol/L时,cmc从8.0×10^(-3)mol/L降至8.0×10^(-4)mol/L,γ_(cmc)从36.00 mN/m降至31.45 mN/m。同时,在SMLT溶液中加入Ca^(2+),SMLT/水体系的二元相图出现胶束溶液相区、蠕虫胶束相区、六角束液晶相区、层状液晶相区和胶束-晶体相区,原有的双水相区消失,胶束-晶体区变大。在考察Ca^(2+)浓度对SMLT溶液黏度的影响时,发现当SMLT/Ca^(2+)的摩尔比为1时,SMLT溶液增黏效果明显,摩尔比为0.6时溶液析出固体。选择质量分数为20%的SMLT溶液进行流变性能测定,根据样品流变曲线,发现其具有剪切变稀的现象,冷冻透射电镜显示有蠕虫胶束的形成。

蠕虫状胶束的形成及其油田应用

通过控制内外因素调节蠕虫状胶束的生长是胶束研究的热点之一。介绍了表面活性剂基蠕虫状胶束的形成机理,评述了分子结构、助溶盐、助表面活性剂等对蠕虫状胶束形成的影响,介绍了通过控制温度、pH值、光、电来制造响应型材料的新方法。讨论了蠕虫状胶束在油田开采中作为清洁压裂液等功能材料使用的优点和难点,认为其经济性和高效性应受到重视。

湘西震旦系留茶坡组炭质宏化石初步研究

初步研究表明,留茶坡组中部黑色页岩中化石呈炭质压膜状保存,主要包括长绳状或带状宏观藻:Chenlidenella spiralis gen.et sp.nov.,Longifuniculum dissutum Steiner,Erdtmann and Chen,1992, Longitaenina triphyllus gen. et sp. nov., L. rhodina gen. et sp. nov., L. laceolatus gen. et sp. nov.;直立不分枝的管状宏观藻Longfengshania elongata Duan et Du,1985, L. elliptic-ulum sp. nov, Paralongfengshania oblong sp. nov. Miaohenella hunanensis（Steiner, Erdtmann and Chen,1992）, M. rhomba Ding,1996, M. taenina sp. nov., Cystoculum catenuatus gen. et sp. nov.;末端存在二歧式分叉的丝状宏观藻:Sectoralga bibarbatus sp. nov., S. typica Hu,1996,S. capillaceus sp. nov., S. umbellulata Hu,1996和水母状化石Taoyuania ovatoides gen. et sp. nov., Liaonanella giganta sp. nov., Wulingshania canopse gen. et sp. nov.及蠕虫状化石 Wenshanwania simplex gen. et sp. nov.等。从地层对比上看,上述化石可能与伊迪卡拉动物群为同一时期的产物。晚震旦世晚期留茶坡组中类水母化石的出现是我国晚震旦世生物演化史上一次重要事件,以类水母等软躯体动物和高分异度的宏观藻类?

一种新型介孔磷酸硅铝(SAPO)分子筛的合成及表征

以Silicate-1晶种为硅源,水热合成了一种新型介孔磷酸硅铝(SAPO-1)分子筛,并且通过X射线粉末衍射、红外光谱、透射电镜、扫描电镜、热重分析、N2吸附/脱附和氨气程序升温脱附(NH3-TPD)等多种手段对产物进行了表征.红外光谱表明,Silicate-1导向剂成功地引入了介孔骨架;氨气程序升温脱附(NH3-TPD)结果表明,SAPO-1具有较强的酸性.催化结果表明,SAPO-1在大分子催化反应中有较高的活性.

蠕虫状有序介孔二氧化硅合成实验的探讨

采用廉价的环境友好的工业化生产的阳离子烷基糖苷作为模板剂,在pH 9的弱碱性条件下水解正硅酸乙酯得到了蠕虫状有序的介孔二氧化硅材料。实验结果表明,最佳反应条件为:反应温度21℃,各反应物的质量比CAPG∶水∶氨水∶TEOS=0.9∶20.0∶1.1∶2.0。所得到的二氧化硅材料具有规则的蠕虫状结构,有较好的水热及热稳定性,经550℃焙烧4 h和100℃水热处理54 h后,蠕虫状孔道结构仍保持良好,表明其可作为一种良好的催化剂载体。此方法所选用的导向剂具有绿色、天然、低毒、低刺激等优点,符合绿色化学的发展趋势,并有利于将其向工业化生产推进。

陕南末元古代高家山生物群主要化石类群及其特征

末元古代高家山生物群是以骨骼化石为主 ,兼有软躯体后生动物及宏观藻类化石的一个多门类化石组合 ,是目前已知最早且最为多样化的骨骼化石生物群。化石主要产于上震旦统灯影组高家山段中上部 ,时限约5 6 5— 5 43Ma。目前虽然尚难对其进行系统的生物学分类 ,但根据化石的形态特征可以划分为以下几个类群 ,即具矿化壁的骨骼类群 ,包括管状化石、锥管状化石、瓶状化石、球状化石、杯状化石和疑难化石等 ,以及蠕形动物化石类群 ,遗迹化石类群和宏观藻类化石类群等。还选取与其同时代且特征较为相似的峡东西陵峡生物群和南非纳米比亚纳玛生物组合进行比较。

仿尺蠖式气压驱动管道清洁机器人的设计

设计了一种用于管道清洁的气压驱动机器人,机器人由清洁作业单元、纵向驱动单元、横向支撑单元和气压系统四部分组成。清洁作业单元利用气压马达驱动合金刀头旋转,清洁管道内壁;纵向驱动单元由两套相同的驱动模块构成,两套相同的驱动模块通过万向虎克铰连接,带动整个机器人沿管道内壁运动;横向支撑单元通过滑轮与管道内壁接触,为清洁作业单元和纵向驱动单元提供支撑力;气压系统为整个机器人的工作提供动力源和控制信号。提出了机器人的仿尺蠖式运动方式,整套机器人机构简单、设计可靠,可以实现远距离、复杂工况的管道内壁的清洁工作。

晚震旦世高家山生物群化石新材料

对张录易等 (1992 )所建立的管状骨骼化石Qinella属进行重新修订 ,根据基本宏观特征、壳面装饰和壳壁套管式结构等将QinellashaanxiensisZhang ,LietDong ,1992和QinellalijiagouensisZhang ,LietDong ,1992归入SinotubulitescienegensisMcmenamin ,1985 ,而Qinella属征限定为管壳外表面光滑的多层壁套管式结构。对Chenella的属征进行厘定 ,建立ChenellaregularisZhangetHua一新种。根据口部特征的似吸盘状构造 ,建立蠕形动物—新属YudaiellaZhangetHua。

清洁压裂液配方优化及流变性能研究

考察了清洁压裂液的流变特性,确定了主剂和主剂质量分数,评价了不同无机和有机胶束促进剂对主剂的影响,确定了添加剂类型和添加剂质量分数,形成清洁压裂液配方。利用黏度计和流变仪对清洁压裂液的流体类型进行了探讨,考察了温度、无机盐、有机质、pH值等因素对压裂液性能的影响。试验结果表明:温度、无机盐和有机物对体系影响较大,pH值影响不大。低温透射电子显微镜(Cryo-TEM)表征结果表明该清洁压裂液体系由大量缠绕的蠕虫状结构组成,该结果与流变学结果一致。

Bola反离子诱导的高粘弹十六烷基硫酸钠蠕虫胶束溶液(英文)

利用稳态和频率扫描研究了十六烷基硫酸钠(SHS)与Bola盐(N,N'-双乙基二甲基-α,ω-乙烷溴化铵(Bola2Et)或N,N'-三甲基-α,ω-丁烷溴化铵(Bola4))混合体系的流变行为.实验结果表明两个体系均在45℃时形成了长蠕虫胶束,溶液呈现出高粘弹性,尤其是SHS/Bola2Et溶液表现出很高的弹性,零剪接粘度高达2520Pa's,表观上呈现胶状.这些结果归因于在Bola反离子诱导下,表面活性剂SHS与Bola反离子形成了静电吸引的2:1结构复合物.由于这两个Bola反离子的联接链长度均短于季铵离子的静电平衡距离,因此形成的复合物在形状上有利于蠕虫胶束生成.作为对比,添加简单的四甲基铵反离子无法诱导SHS形成蠕虫胶束,溶液仅呈现低粘度.

碳量子点掺杂的蠕虫状胶束

以富勒烯生产过程中的副产物炭灰为原料,利用酸回流法制备了表面含有羧基的碳量子点(CQDs)。将所制备的CQDs代替传统有机酸,发现其与十四烷基二甲基氧化胺(C_(14)DMAO)在水溶液中能形成蠕虫状胶束。考察了CQDs质量浓度、pH等对蠕虫状胶束流变性质的影响。结果表明,CQDs质量浓度的增加和溶液pH值的降低均有利于蠕虫状胶束的形成。利用低温透射电镜可以原位地观察到蠕虫状胶束和CQDs的存在。CQDs外围-COOH解离出的H^+可以使C_(14)DMAO质子化为C_(14)DMAOH^+,而C_(14)DMAOH^+与C_(14)DMAO之间形成的氢键是蠕虫状胶束形成的主要驱动力。以上结果表明,CQDs可以有效地诱导C_(14)DMAO形成蠕虫状胶束。

蠕虫状链模型的均方末端距修正

蠕虫状链是一种适用于从柔性到刚性的大分子链模型,尤其适合半刚性和刚性高分子链,因此运用此模型分析多肽与DNA等生物大分子链构象的研究越来越多.在简单介绍蠕虫状链模型的基础上,分析了运用蠕虫状链模型推导均方末端距时存在的问题,并提出了采取自由旋转链模型处理的解决方法,有助于正确理解与应用蠕虫状链模型.