烷氧基羟丙基三甲基溴化铵/正丁醇/水体系的相行为

绘制了3-十二烷氧基-2-羟丙基三甲基溴化铵(R12TAB)／正丁醇／水三元体系的相图，确定了不同区域的范围。用电导法测定了微乳液区域内由W／O型微乳液经双连续结构到O／W型微乳液的变化过程。用^2HNMR和差示扫描量热法(DSC)并与液晶纹理对照，研究了该体系的液晶结构特点。结果表明，固定R12TAB和正丁醇的比例，随含水量的增加，体系的液晶相结构发生如下变化，从层状液晶→层状与六角状液晶共存→层状、六角状与立方状液晶共存→层状液晶与微乳液共存。     

十二烷基硫酸钠/正丁醇/正庚烷/水微乳液性质研究

25℃时,绘制十二烷基硫酸钠(SDS)/正丁醇/正庚烷/水体系在不同R值(水和SDS的摩尔比)时的相图,得出该体系能形成W/O微乳液的配比为:正丁醇的质量分数在25%~60%,正庚烷的质量分数在0~80%。该体系在室温下能够形成较大范围的W/O单相微乳液区,R值对微乳区的面积和所在的位置无太大的影响。采用电导率曲线讨论了加水稀释过程中,体系由W/O型→双连续型→棒状液晶→层状液晶→双连续型→O/W型的微观结构转变。采用稀释法求得其W/O型微乳液体系的结构参数,结果表明:体系的水内核半径Rw在讨论的范围内随VH2O、R值的增加而增大。含水量增加,自由能-ΔGcO→i降低,对微乳液体系的稳定不利;含水量越低,越有利于微乳液的形成和稳定。     

不饱和聚酯树脂微乳液的研究(Ⅰ)不饱和聚酯树脂的微乳化

合成了不同磺酸盐含量的三种不饱和聚酯，通过拟三元相图分析磺酸盐含量、苯乙烯、不同正构醇和水组成的体系对微乳区域的影响。研究结果表明，磺酸盐不饱和聚酯同苯乙烯互溶的前提下，磺酸盐含量越大，其微乳液增溶的水量越大；磺酸盐含量一定时，苯乙烯含量越小，其微乳液增溶的水量越大；正构醇质量分数为在2％～10％范围内，其微乳液增溶的水量最多；三种醇相比较，正丁醇体系的微乳区是W／O型向O／W型过渡的连续区域，正丙醇体系的O／W型微乳液区明显不同于正丁醇体系，正戊醇体系不能形成水包油型的微乳区。     

MAP-乙醇-水三元相图的绘制及其在纳米羟基磷灰石制备中的应用

绘制了单烷基磷酸酯(MAP)-乙醇-水三元体系在30℃的相图,用电导法结合偏光显微镜等测试仪器将相图分为W/O微乳区、O/W微乳区、MAP过量区、微乳液与液晶共存区和液晶单相区。选取相图中W/O微乳区内的一个液相组分点,制备了纳米羟基磷灰石。小角X射线衍射、透射电子显微镜分析结果显示:纳米羟基磷灰石具有规则排列的层状微观结构。     

NP-10/硝酸钠水溶液体系的相行为与流变性

研究了浓度为0.02mol/L的硝酸钠水溶液中非离子表面活性剂NP-10的相行为与流变学性质。随NP-10质量分数的增加,体系中依次可以形成胶束,六角状、立方状和层状液晶以及反胶束。六角状和立方状液晶的流变学性质可以用Maxwell模型说明。用已经验证的经验方程对层状液晶的流变学特征做出了表述。     

正丁醇对二(2-乙基己基)琥珀酸酯磺酸钠微乳液体系的影响

通过在二(2-乙基己基)琥珀酸酯磺酸钠(AOT)/正庚烷/水的三元体系中加入正丁醇,得到了新的四元体系。绘制了25℃时AOT/正丁醇/正庚烷/水四元体系能够稳定存在的相图,发现在一定R值(水和AOT的摩尔比)条件下该相图出现了分为两个区域的现象。利用电导率数据研究了由W/O型微乳液→双连续微乳液→棒状液晶→层状液晶→双连续微乳液→O/W型微乳液的结构转变。通过稀释法求得AOT/正丁醇/正庚烷/水微乳液体系的结构参数,结果表明:含水量增加,两个区域的自由能-△G0c→i都减小,对微乳液体系的稳定不利;含水量越低,越有利于微乳液的形成和稳定;AOT/正丁醇/正庚烷/水四元体系比以AOT作表面活性剂的三元体系有更大的微乳液区域,是一个适合制备所需功能性纳米粒子的体系。     

吐温-80/对二甲苯/1,2-丙二醇水溶液拟三元体系相图研究

采用稀释法绘制了吐温-80/对二甲苯/1,2-丙二醇水溶液拟三元体系的25℃相图,利用电导法测定了其中微乳液的微观结构。结果表明：体系中包含单相微乳区、两相分层区、白色乳液区三部分,其中微乳区又分为油包水（W/O）微乳区、双连续区（B.C.）、水包油（O/W）做乳区三部分。另外。考察了醇水溶液中醇的质量分数及温度对撒乳区域范围的影响,发现醇的质量分数越高,微乳区域范围越大;温度越高,O/W微乳区域范阻越小。经稳定性实验表明：O/W微乳液稳定.     

助乳化剂对化妆品乳液稳定性和液晶性的影响

以硬脂酸蔗糖酯和失水山梨醇硬脂酸酯的复配物（SSE）为主乳化剂，十六／十八醇及甘油为助乳化剂制备含液晶乳液化妆品。通过观察乳液的温度稳定性和液晶性，用三元相图研究助乳化剂含量对此乳液体系液区的影响。实验条件下，用该乳化剂体系可获得较好的液晶化妆品乳液，总之，较高的助乳化剂量有利于乳液的温度稳定性和液晶性，但助乳化剂量较低时经合理配方也能获得稳定的液晶乳液，其中含3％高碳醇和5％甘油的乳液稳定性及液晶性均较好，5％高碳醇和3％甘油的助乳化剂体系不宜采用。     

微乳液体系拟三元相图及其微观结构的研究

在25℃下绘制了十六烷基三甲基溴化铵(CTAB)/正辛醇/正辛烷/水的拟三元相图,研究了CTAB与正辛醇质量比分别为1∶2,1∶3,2∶3下体系的微乳区以及微乳区的变化,并采用电导率法研究了微乳液的微观结构,将整个微乳液单相区分为油包水(W/O)微乳区、水包油(O/W)微乳区和B.C.双连续区,确定了微乳液体系形成区域并比较了各质量比下的微乳区。研究结果表明:当CTAB/正辛醇的质量比为2∶3时,能够得到较大且稳定的微乳区域;在此条件下,当(CTAB+正辛醇)/正辛烷的质量比为3∶7时,微乳液区域中存在最高溶水点且微乳液区域最大。该研究从热力学相图原理上为纳米颗粒的可控制备提供了理论依据。     

反相微乳液法制备高溶度ZrO2陶瓷墨水(Ⅰ)

尝试采用新颖的反相微乳液法制备陶瓷墨水，为了获得高溶度陶瓷墨水，对反相微乳液体系优选进行研究，着重就Triton x-100/醇／烷／水体系，采用目测法，分光光度法，电导率法和离心分离法，分别考察了不同醇，烷配伍时体系的稳定性和相关物理性质，根据这些性质是否突变以确定体系是否发生相变，给出了体系拟三元相图。实验表明，在20℃时Triton x-100／正己醇／环己烷／水反相微乳液体系表现优异，当Triton x-100与正醇的质量比为3：2时达到最大范围的反相微乳液区，最大溶水量时的最佳组成为Triton x-100:正己醇：环己烷：水＝19．1％：12．8％：23．7％：44．4％（质量比）。     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

Microwave Dielectric Properties of CaTiO3-CaAl1/2Nb1/2O3 Ceramics Doped with Li3NbO4

The microwave dielectric properties of CaTi_{1− x} (Al_1/2Nb_1/2) _x O₃ solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO₃. The substitution of Ti⁴⁺ by Al³⁺/Nb⁵⁺ improved the quality factor Q of the sintered specimens. A small addition of Li₃NbO₄ (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛ_r) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τ_f) of −2 ppm/K. Li₃NbO₄ as a sintering additive had no harmful influence on τ_f of ceramics.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

Characteristic Spherulitic Microstructure in Partial-Melt-Processed YBa2Cu3Ox/HfO2

The microstructure of partial-melt-processed YBa₂Cu₃O _x /HfO₂ has been studied by transmission electron microscopy. A characteristic spherulitic microstructure is formed in the system. A model for the growth mechanism has been proposed. The critical heterogeneous nucleation of the YBa₂Cu₃O _x phase appears to occur from the melt in an epitaxially controlled manner on CuO particles. Subsequent growth of YBa₂Cu₃O _x platelets from the nucleus region is repeatedly interrupted by the nucleation of hafnium-rich phases in the liquid at the solid/liquid interface in a manner that again appears to be epitaxially controlled and that promotes the splay of the c orientation of the YBaCuO grain.