Microstructure of carbonaceous mesophase spherule

Carbonaceous spherules of mesophase were examined by transmission electron microscopy (TEM) and X-ray diffraction to precisely clarify its structure. A series of thin sections were cut from a single spherule with a microtome, and the three-dimensional lamellar structure of the spherule investigated. From 002 dark-field images and selected area electron diffractions (SAD), it was observed that the spherule was of the Brooks-Taylor type, with the lamellae being parallel even at the poles of the spherule. Structural changes within the spherule was studied following carbonization and graphitization. The structure of the resultant coke was essentially that of spherule of mesophase. Size of the lamellae increased as well as. The number of stacking lamellae also increased, but a rapid increase was not seen. The spherules of mesophase show a high degree of homogeneity and an excellent degree of graphitization.     

Sol-gel synthesis, microstructure and adsorption properties of hollow silica spheres

Spherical colloidal particles with a hollow interior and a mesoporous shell are particularly useful for drug delivery and release because such spheres combine the unique properties of hollow interior (for storing the drug) with mesoporous shell (for controlled release). Hollow silica spheres (HSS) with a mesoporous shell were prepared via a sol-gel process in the presence of dual templates polystyrene spheres and cetyltrimethylammonium bromide for creating the hollow core and mesopore shell. The effect of the ratio of silica precursor over polystyrene spheres on particle morphology and pore structure of the HSS was investigated. The adsorption kinetics of methyl blue on the HSS was evaluated and correlated with the mesoporous shell structure.     

A蛋白中空纤维膜吸附分离单克隆抗体

首先以人γ－免疫球蛋白为实验物系，对Ａ蛋白中空纤维亲和膜的吸附性能进行了考察，然后应用亲和膜，从小鼠腹水上清液中直接吸附小鼠抗人绒毛膜促性腺激素单克隆抗体，纯化的单克隆抗体经ＳＤＳ－聚丙烯酰胺凝胶电泳检测达到电泳纯。     

U型中空纤维膜水力特性的模型分析

依据水力学原理,建立了竖立式U型中空纤维膜出水量及内压的数学模型,对其结果的理论分析表明：在相同的水头作用下,纤维膜流量随距出水口距离的减小而呈比例增加,但在出水水头较高时,增加的速率要大于出水水头较低时增加的速率;类似地,在纤维内部的不同位置,流量随出水作用水头的增加而增大的速率也是不同的,离纤维出口越近,这种速率的增加就越快,越明显．因此,要想增大出水流量,应尽量提高出水的作用水头,另外还可以在一定范围内增加纤维的长度;纤维内压随距出水口距离的减小而迅速减小,曲线呈类抛物线的形状;离出水口越远,纤维内压随出水水头的增大而增加的速率越大;流量与内压成直线关系,纤维内部距出水口越近,内压随流量增加而增加的梯度越小;由于液体黏度的影响,温度升高,流量增大;但温度越高,流量的增加梯度越小。     

Agglomerating vibro-fluidization behavior of nano-particles

An experiment study of agglomerating fluidization behavior of three kinds of nano-particles (SiO₂, TiO₂, ZnO) in vibro-fluidized bed (VFB) has been performed. At certain amplitude (3 mm) of vibrations applied, the minimum fluidization velocity decreases, whilst the equilibrium pressure drop increases with increase in the vibration frequency. The minimum fluidization velocity is nearly independent of the vibration amplitude at almost constant frequency of about 40 Hz, whilst the equilibrium pressure increases. Using the linear regression, the Richardson–Zaki exponents of three kinds of nano-particles have been calculated. R–Z analyses indicate that the particulate fluidization degree of cohesive particles can be greatly improved by vibration force.     

Operating characteristics of the hollow anode glow discharge ion source

In this work, a new shape of a glow discharge ion source with axial extraction has been designed and constructed. High output ion beam current can be extracted axially in a direction normal to the discharge region without using extraction system. Optimization of the distance between the anode and the cathode has been determined using argon gas. It is found that the optimum gap distance between the anode and the cathode is equal to 3.5 mm, where stable discharge current and maximum output ion beam current can be obtained. The discharge characteristics of the ion source at different operating gas pressures have been measured at this optimum distance between the anode and the cathode. A disk of Teflon insulator has been put between the anode and the cathode. This disk was covering the cathode area and reducing the discharge area on the cathode surface for discharge confinement, therefore, a higher output ion beam current could be obtained.     

微反应器法纳米颗粒制备技术

微反应器法以其特殊的微反应环境而在纳米颗粒的制备中受到越来越广泛的重视,从微反应器的组成和性质入手,介绍了微反应器内纳米颗粒的形成机理及反应特点,举例说明了该法在纳米颗粒制备中的应用,对该法在纳米颗粒制备中的前景作了展望。     

Protein adsorption characteristics of plasma treated polyurethane surfaces

The effect of various plasma surface treatments on the protein adsorption characteristics of two polyurethane elastomers (Acushnet E417-0 [ACx] and Texin 480 AR [TN]) were studied. Both substrates are based upon diphenylmethane 4,4-diisocyanate (MDI) hard segments and polyester soft segments. Adsorption characteristics of the untreated samples were initially established, followed by plasma treated surfaces. Contact angle and 2 h albumin adsorption were determined. (1) Results of this study indicate that the protein adsorption characteristics of crosslinked substrate ACx is more linear than that of non-crosslinked substrate TN. Further, substrate TN adsorbs seven-fold greater protein at a rate four times higher on its surface than ACx.N,N-Ethylene bis (stearamide), a processing aid used in substrate TN, may encourage greater protein adsorption on substrate TN and variation in the soft segment mobility between the substrates also may affect their adsorption characteristics. (2) Plasma treatments using CH₄ and/or C _x F _y chemistries increased the contact angle for both substrates while those with O₂ and O₂/CF₄ decreased the contact angle for the substrates considered. In general, the contact angle of the substrates exhibiting greater protein adsorption was smaller.     

中空层状羟基磷灰石微球对溶菌酶的吸附与缓释研究

利用锂钙硼玻璃在磷酸盐溶液中的原位转化反应制备表面多孔且具有中空层状结构的羟基磷灰石(HA)微球,以溶菌酶为蛋白的药物模型,研究了中空层状结构的羟基磷灰石微球对溶菌酶的吸附及缓释特性,结果显示,中空微球对不同浓度的溶菌酶溶液,具有不同的吸附机理,当溶菌酶溶液的浓度低于0.8mg/mL时,溶菌酶的吸附主要发生在微球的外表面,符合Langmuir模型,释放速率较快,48h内基本释放完全;当溶菌酶溶液的浓度高于0.8mg/mL时,溶菌酶扩散进入微球内部及球壁的微孔中,使得吸附量显著增加,满足Henry吸附模型,溶菌酶的释放周期明显增加,可持续释放800h,微球对蛋白具有很好的缓释效果。     

中空型分子印迹聚合物的制备及其对4-甲基二苯并噻吩的吸附性能研究

以SiO2为载体,4-乙烯基吡啶为功能单体,结合牺牲载体法合成了一种具有特异性识别4-甲基二苯并噻吩的中空型分子印迹聚合物。利用傅立叶变换红外光谱、氮气吸附实验、扫描电镜对形态结构进行了表征。通过在模拟油中的静态吸附试验,对印迹聚合物的吸附性能进行了研究。结果表明,在SiO2表面成功地合成了具有多孔结构的分子印迹层,经过牺牲载体法处理后得到的中空分子印迹聚合物具有更好的表面特性,提高了吸附性能。中空型分子印迹聚合物对4-甲基二苯并噻吩表现出良好的特异性识别性能,吸附动力学满足Langergren准二级动力学方程,等温线符合Freundlich等温线模型,吸附热力学研究表明吸附是自发的吸热过程,在328K下的吸附容量为18.31498mg/g,吸附平衡时间为3h。     

聚砜中空丝支撑膜结构及性能的研究

聚砜为材料，用特制的喷丝头，以干湿法制备了适用于ＰＤＭＳ－ＰＳ复合膜的ＰＳ中空纤维多孔支撑膜，研究了纺丝液配方、温度及纺丝速度、蒸发距离等有关工艺条件对ＰＳ多孔底膜结构的影响，用扫描电子显微镜观察分析其微观结构，对ＰＳ多孔底膜结构与ＰＤＭＳ－ＰＳ复合膜透气性关系进行了初步的讨论。研制的用于空气富氧的直径１００ｍｍ×１０００ｍｍ ＰＤＭＳ－ＰＳ中空纤维复合膜组件的性能参数为：透量１２Ｎｍ＾３／ｈ·０     

羟基磷灰石内连通空心球陶瓷支架的形貌特征及力学性能

利用聚苯乙烯微球模板,采用负压抽滤注浆工艺制备了羟基磷灰石(hydroxylapatite,HA)内连通空心球陶瓷支架,分析了制备工艺对空心球陶瓷的形貌特征和力学性能的影响,并研究了孔隙率与压缩强度的关系.结果表明,空心球陶瓷支架具有连通球形孔及连通球体间隙的独特复合孔结构;当注浆2次,浆料固含量为0.5g/ml时支架的孔壁完整,表面形态有利于骨细胞生长;通过改变工艺参数,得到HA空心球陶瓷的孔隙率为61%～90%,压缩强度为1.1～6.9MPa,孔隙率P与压缩强度σf的关系符合ln(σf)=ln(σf0)-bP方程.     

Correlation between structure and adsorption characteristics of oriented polymers

In a more or less swollen state the methods by which the fiber structure is determined provide more realistic information about their properties and structure in wet conditions, because of the swelling and alteration of fiber structure. These results, however, of sorption analyses are very rarely in accordance with those obtained from structural analyses. One such ”wet” method is the iodine sorption test. The iodine sorption test was originally proposed by Schwertassek [1] and since then has been constantly modified by other researchers [2–7]. In this presented work the correlation between different structural parameters, iodine sorption (ISV) and conventional sorption analyses (water vapor sorption and water retention power) of polyamide 6 (PA 6) and cellulose fibers was studied. The results demonstrate that the iodine sorption value best correlates with the degree of crystallinity and the perfection of the crystalline phase of both polyamide and cellulose fibers. The correlation is linear. Received: 25 August 2000 / Reviewed and accepted: 28 August 2000     

The adsorption characteristics of osteopontin on hydroxyapatite and gold

The adsorption of osteopontin on hydroxyapatite (HA) and reference gold (Au) surfaces was studied at different protein bulk concentrations over the temperature range 295-317 K, using quartz crystal microbalance with dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). The QCM-D protein adsorption studies were complemented with polyclonal antibodies to examine the availability of protein sequences on the resulting protein layer. The QCM-D and XPS results show that the osteopontin surface mass uptake is larger on Au as compared to HA surfaces within the range of experimental conditions examined (protein bulk concentrations and temperature range), in accordance with the formation of a more compact protein film on Au. The specific antibody binding to the resulting adsorbed osteopontin layer as measured by QCM-D further confirms that the protein packing and conformational/orientational changes occurring during OPN adsorption on Au and HA are different, since fewer antibodies are observed to bind per OPN molecule on Au as compared to HA. The adsorption process on the respective surfaces was modeled using both the Langmuir and Hill adsorption isotherms, and from these isotherm curves, the Gibbs free energy, ?G, of the osteopontin adsorption was determined. The estimated ?G values indicate that the osteopontin molecules have a high affinity towards Au, while a lower affinity is observed between osteopontin and HA. By examining the changes in ?G as a function of temperature, we additionally find that the osteopontin adsorption on HA and Au is endothermic and driven by an increase in entropy.     

Synthesis of hollow ZrO2 mesopores microspheres with strong adsorption capability by the yeast bio-template route

In this work, cage-like ZrO2 and hollow ZrO2 microspheres with high surface area and strong adsorption capability were successfully synthesized by microwave- ethanol-thermal method using yeasts as bio-template. XRD, SEM, EDS and BET were used to characterize the products. The results show that these micropheres have a size of about 2-3 microm and are composed by ZrO2 particles of 30-40 nm. The maximum specific surface area of them can reach to 384.780 m2/g and there are presences of the inhomogeneous mesopores. Moreover, the template can be removed and tetragonal phase ZrO2 can be obtained without using calcinations, which greatly simplifies the experimental procedure. We also studied the adsorption capability of cage-like ZrO2 and hollow ZrO2 microspheres to methyl orange, the highest adsorption percent was up to 99.5%. The adsorption isotherm conforms to Freundlich equation.     

Influence of adsorption on current-voltage characteristics of discontinuous metal films

The influence of the adsorption of N₂, O₂, H₂ and H₂O on the forming process and anomalies in the current-voltage (I-V) characteristics of discontinuous gold films were investigated. The forming of films results in conductivity channels through which the current mainly passes. The forming process and the anomalous I-V characteristics are highly sensitive to the presence of a layer of adsorbed H₂O on the substrate.     

表面活性剂在纳米粉体制备中的应用

本文论述了表面活性剂在Al2O3纳米粉体制备、改性等方面的应用,并简要介绍表面活性剂在纳米粉体修饰中的作用。     

添加剂和纳米粒子强化溴化锂水溶液／氨水吸收特性研究进展

吸收式制冷以其节能、环保等诸多优点得到了越来越广泛的应用。本文总结与分析添加剂和纳米粒子强化溴化锂水溶液及氨水吸收特性的机制和相关实验研究的发展现状。针对吸收式制冷系统中吸收器传质系数和换热系数小而导致的制冷效率低的问题,很多学者进行了添加剂和纳米粒子对吸收过程影响的实验研究,并据此采取措施增大传质传热效率。实验主要包括以下几个方面：表面张力实验、静态池吸收实验、降膜吸收实验和氨水鼓泡吸收实验。实验结果均表明添加剂和纳米粒子可以提高吸收器中溴化锂水溶液及氨水的传热传质性能。该研究对于提高吸收式制冷系统的制冷效率有很大帮助,同时为该技术在实际系统中的应用奠定基础。