混合表面活性剂双水相性质的研究

本文利用电导法及冷冻蚀刻实验技术研究了正负离子表面活性双水相上相中的液晶结构状态及其相关性质。在双水相相体积比一组成关系曲线上及上相电导率—组成曲线上,均存在明显的转折。转折处组成是有偏光现象的双水相与无偏光现象的双水相的分水岭,立方液晶导电能力与容纳水的能力强于层状液晶或六方液晶。冷冻蚀刻实验证实了无偏光现象的立方液晶的存在。本文对一些机理进行了讨论。

醇对正负离子表面活性剂双水相性质的影响

The effect of alcohol on the aqueous two-phase system properties of SDS/CTAB/H 2O/Na 2SO 4 system was studied by the pseudo ternary phase diagram. The electrostatic forces (both attraction and repulsion) between cationic surfactant and anionic surfactant decreased because of the interaction of alcohol hydroxyl group and surfactant polar group. As a result, the phase area width of aqueous two-phase system increased. Long chain alcohol (more than five carbonatoms), which was in high concentration in the SDS/CTAB/H 2O/Na 2SO 4 system, caused the anionic aqueous two-phase system area to vanish and the cationic aqueous two-phase system area to become wider. The CTAB rich phase turned from top phase to bottom phase.

全氟辛酸钠-辛基三乙基溴化铵混合水溶液在油面上的铺展研究

氟表面活性剂水溶液在油面上的铺展是水成膜泡沫灭火剂的基础。通过研究全氟辛酸钠(SPFO)与辛基三乙基溴化铵(C_8NE)复配后的水溶液在环己烷、正庚烷、90号汽油上的铺展行为,表明阴、阳离子表面活性剂之间产生的强烈增效作用不仅提高了铺展性能,使本来不能铺展的单一SPFO和C_8NE水溶液变为铺展,而且大大降低了氟表面活性剂的用量。考察两种表面活性剂不同混合比例及总浓度对铺展速度、铺展量、临界快速铺展浓度的影响,并通过表面张力的测定从机理方面进行辅证。在所研究的浓度范围内,SPFO-C_8NE混合体系的总浓度越高,混合比越接近等摩尔,越有利于快速铺展和增大铺展量。等摩尔SPFO-C_8NE混合溶液在不同油面上铺展量从大到小依次为环己烷、90号汽油、正庚烷。

表面活性剂复配制备稳定的固体脂质纳米粒混悬液(英文)

目的:表面活性剂在固体脂质纳米粒的制备过程中扮演着重要角色,为规避药物对体系的影响,本文选用4种表面活性剂制备了空白而具有良好物理稳定性的固体脂质纳米粒混悬液。方法:用激光散射粒度仪和Zeta电位分析仪(LD)检测平均粒径、颗粒分布范围和Zeta电位,另外还进行了DSC热分析和颗粒形态的TEM观察。结果:离子型表面活性剂脱氧胆酸钠可以提高纳米粒的Zeta电位从而提高系统物理稳定性,但乳化率低;非离子乳化剂Pluronic F-68可以起到空间稳定的作用从而避免胶体系统中颗粒的聚结。结论:4种表面活性剂的复配[两种非离子乳化剂(Pluronic F-68和Tween80),离子型表面活性剂(脱氧胆酸钠)以及卵磷脂]可以制备稳定6个月而不分层的纳米混悬液。

中药半仿生提取法的研究进展

半仿生提取法符合药物经胃肠道转运原理,适合工业化生产,既体现中医治病综合成分作用的特点,又有利于用单体成分控制制剂质量,它是比常规提取方法更优的中药和方剂的药效物质提取新技术。它具有科学性和实用性,有着广泛的推广应用前景。

SDS/CTAB/H_2O的双水相性质及萃取作用

测定了SDS CTAB H2 O Na2 SO4 系统的双水相相图及牛血清蛋白和色氨酸在不同区域双水相中的分配系数 ,研究了相关因素对双水相分相时间的影响规律。结果表明 ,体系的相图中存在 2个双水相区 ,盐的种类、浓度及双水相的两相高度之比是影响双水相分相时间的重要因素。物质的疏水程度越大 ,越易被萃取到富表面活性剂相中 ,水溶性小分子物质不能被萃取。当物质的电性与富表面活性剂相有序组合体的电性相反时 。

Binary Adsorption Equilibrium of Benzene-Water Vapor Mixtures on Activated Carbon

Adsorption equilibrium isotherms of benzene in the concentrationrange of 500-4000 mg·m^-3 on two commercial activated carbons wereobtained using long-column method under 30 deg. C and differenthumidity condi- tions. Results show that the benzene and water vaporshave depression effects upon the adsorption of each other and thatthe unfavorable effect of water vapor resembles its single-componentisotherm on activated carbon. A com- petitive adsorption model wasproposed to explore the depression mechanisms of the non-ideal,non-similar binary adsorption systems.

Catalytic Activity of the Black Liquor and Calcium Mixture in CO2 Gasification of Fujian Anthracite

CO2 gasification of Fuijian high-metamorphous anthracite with black liquor （BL） and/or mixture of BL and calcium stuff （BL＋Ca） as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressure. When the coal was impregnated with an appropriate quantity of Ca and BL mixture, the catalytic activity of CO2 gasification was enhanced obviously. With a loading of 8%Na-BL＋2%Ca, the carbon conversion of three coal samples tested reaches up to 92.9%-99.3% at 950℃ within 30min. The continuous formation of alkali surface compounds such as （[-COM], [-CO2M]） and the presence of exchanged Ca, such as calcium phenolate and calcium carboxylates （COO）2Ca, contribute to the increase in catalytic efficiency, and using BL＋Ca is more efficient than that adding BL only, The homogeneous model and shrinking-core model were applied to correlate the data of conversion with time and to estimate the reaction rate constants under different temperature. The corresponding reaction activation energy （Ea） and pre-exponential factor of three anthracites were estimated. It is found that Ea is in the range from 73.6 to 121.4kJ·mol^-1 in the case of BL＋Ca, and 74.3 to 104.2kJ·mol^-1 when only BL was used as the catalyst, both of which are much less than that from 143.5 to 181.4kJ·mol^-1 if no catalyst used. It is clearly demonstrated that both of BL＋Ca mixture and BL could be the source of cheap and effective catalyst for coal gasification.

PEGylation of Hirudin and Analysis of Its Antithrombin Activity in vitro

Hirudin is the most anticoagulant drug found in nature, but its short serum half-life significantly inhibits its clinical anpplication. The PEGvlation of hirudin, the most promising anticoagulant drug, was performed in this paper. The optimal reaction conditions for PEG ylated hirudin were investigated, wh.en the PEGylation react, on.wasconducted under 4℃ after 10h, in the borate buffer at pH 8.5 .with the molar ratio 230 ： 1 of PEG to hirudin, a higher modification extent was achieved. Finally, the bioactivity of PEGylated hirudin was measured in vitro.Compared with unmodified hirudin, 26% of anti-thrombin activity was retained.

Theoretical and Experimental Studies on Interactions of Cationic-Anionic Surfactants

Typical cationic and anionic surfactants were chosen and their interactions were calculated by quantum chemical method. Interaction energies are -0.2378 kJ·mol-1, -3.3394kJ·mol-1 and 0.1204kJ·mol-1 for the molecular pairs with fluocarbon and hydrocarbon chain: C4H10/C5H12, C4F10/C5H12, and C4F10 /C5F12, respectively. When hydrophilic group with cationic and anionicions is introduced, interaction energies are -287.40kJ·mol-1, -311.18kJ·mol-1 and -345.83kJ·mol-1. The results show that there is strong static interaction between cationic and anionic surfactants. It has been predicted that mixed monolayer may be formed and surface activity is enhanced favorably, especially for mixtures of cationic and anionic surfactants with fluocarbon and hydrocarbon chains. The anionic surfactants, sodium octadecylbenzenesulfonate perfluopolyetherbenzenesulonate(ANF-I) was synthesized, mixture effects of ANF-I with sodium octadecylbenzenesulfonate or dodecyldimethyl benzylammonium bromide were studied. The results indicate that the efficiency of mixing increased and the theoretical prediction was testified. These results can provide useful information for the design of new surfactants.

Vanadium oxide nanotubes for selective catalytic reduction of NO_x with NH_3

Vanadium oxide （VOx） nanostructures, synthesized by hydrothermal treatment using dodecylamine as template, were evaluated for the selective catalytic reduction of NOx with ammonia （NH3-SCR）, The effect of solvent type in the reaction mixture （EtOH/（EtOH ＋ H20）） and time of hydrolysis was studied. The obtained materials were characterized by XRD, SEM, TEM and BET, The VOx nanorods （80-120 nm diameter and 1-4 μm length） were synthesized in 25 vol% EtOH/（EtOH ＋ H20） and the open-ended multiwalled VOx nanotube （50-100 nm inner diameter, 110-180 nm outer diameter and 0,5-2 pm length） synthesized in 50 vol% EtOH/（EtOH ＋ H20）. VOx nanotuhes performed the superior NH3-SCR activity under a gas hourly space velocity of 12,000 h-1 at low temperature of 250 ~C （NOx conversion of 893g ＆ N2 selectivity of 100%）, while most of the developed Vanadia base catalysts are active at high temperature （〉350 ℃）. The superior NH3-SCR activity ofVOx nanotubes at low tem- perature is related to nanocrystalline structure, special nanotube morphology as well as high specific surface area.

Effect of Different Potting Mixtures on Growth and Yield of Soybean （Glycine max L.） and Soil Microbial Activity

Soybean （Glycine max： Fabaceae） is a mycotrophic （mycorrhizal） crop grown commercially for human consumption. Seven different fertilizer mixtures, namely cow dung, coir dust, mush room medium waste, saw dust, compost, decaying leaves and field soil with standard dose of NPK （control） were used for this experiment. The variety used was PM 25. Soil microbial activity was measured using CO2 evolution method. The experiment was carried out as a complete randomized block design with five replicates at the rate of eight plants per replicate. Average number of leaves on 25-day and 45-day old plants, shoot-length, root-length, number of pods per plant, wet weight of pod per plant, dry weight of pod per plant, plant wet weight, plant dry weight and seed dry weight per pod were measured. All management practices were conducted according to recommendations of the Department of Agriculture from seed germination to harvesting. Data were analyzed using SAS program （9.1.3）. Highest number of pods/plant （100, 124, 102, 106） and dry-seed-weight in g/plant （12, 14.8, 12, 12） were recorded in those grown in cow dung, compost, decaying leaves and inorganic mixture （control） whereas the lowest pod production （8.7 pods/plant） and seed dry weight （1.0 g/plant） was recorded in saw dust. Instead of inorganic fertilizer there is possibility to use organic potting mixtures like compost and decaying leaves which gave a significant difference in crop productivity as compared to other treatments. Significantly highest mean microbial activity was observed in potting media filled with coir dust.

Performances of super-long span prestressed cable-stayed bridge with CFRP cables and RPC girder

To discuss the applicability of advanced composite carbon fiber reinforced polymer(CFRP) and ultrahigh performance concrete reactive powder concrete(RPC) in super-long span cable-stayed bridges, taking a 1 008 m cable-stayed bridge with steel girders and steel cables as an example,a new cable-stayed bridge in the same span with RPC girders and CFRP cables was designed,in which the cable's cross section was determined by the principle of equivalent cable capacity and the girder's cross section was determined in virtual of its stiffness, shear capacity and local stability. Based on the methods of finite element analysis,the comparative analysis of these two cable-stayed bridge schemes about static performances,dynamic performances,stability and wind resistance behavior were carried out. The results showed that it was feasible to form a highly efficient,durable concrete cable-stayed bridge with RPC girders and CFRP cables and made its applicable span range expand to 1 000 m long around.

Study on Crystallization of Titanium Silicalite Zeolite (Ⅱ)

In order to investigate the rules on formation of zeolite during crystallization of titanium silicalite zeolite (TS-1) the X-ray diffractometry and Foulier transform infra-red spectrometry were applied to track the process of crystallization of titanium silicalite zeolite. The research results revealed that at the initial stage of crystallization the interactions between silica gel and titania gel in the polymer blend could gradually lead to the formation of tiny crystal nuclei with complicated structure that could slowly grow up to form molecular sieves. Quite different from the conventional zeolites that use the acid sites as the catalytically active centers, the oxidative reactivity of the titanium silicalite zeolite was not proportional to its crystallinity and is associated with the oxidative centers of titanium contained in the zeolite.

Dynamic separation of Xe and Kr by metal-organic framework and covalent-organic materials： a comparison with activated charcoal

We systematically investigate dynamic separation of Xe and Kr at room temperature using four representative porous materials(Cu-BTC, ZIF-8, COP-4 and activated carbon(AC)). Results indicate that among the four materials, Cu-BTC not only shows the highest retention volume per gram(V_g=788 m L g^(-1), which is 1.8 times of activated carbon(436 m L g^(-1))) under flowing condition, but also can separate 350 ppm Xe from 35 ppm Kr mixture in air with a high Xe/Kr selectivity of 8.6 at room temperature and 200 k Pa, due to its suitable pore morphology, open metal sites, small side pockets in the framework. Moreover, the Cu-BTC also performs well on individual separation of Xe, Kr, CO_2 from five-component gas mixture(Xe:Kr:CO_2:Ar:N_2= 1:1:1:1:0.5, V/V) and has the longest retention time for Xe(20 min) in gas chromatographic separation, suggesting that it is a good candidate for potential applications as polymeric sieves.

Realization approach of Pd-only three-way catalysts with high catalytic performance and thermal stability

Pd-only three-way catalyst （TWC）, Pd supported on washcoating （the mixture of alumina and Ce-Zr solid solution）/cordierite, was prepared and its catalytic performance and the operation window （2-value） at 450 ℃ were evaluated with the simulated automotive exhaust feed gas. Surfactants such as Tween-80 and Span-20 were added in the process of preparing the catalyst in order to improve the thermal stability and catalytic performance of Pd-only TWC. The fresh and aged catalysts at 1000 ℃ for 4 h were characterized by low-temperature N2 adsorption, XRD, XPS, and H2-TPR techniques. The results show that the presence of surfactants in the synthesis slurry could influence the physicochemical properties of the final Pd-only TWC. The FTS catalyst prepared with the mixed surfactant of Tween-80 and Span-20 exhibited excellent three-way catalytic performance. After being aged at 1000℃ for 4 h, the catalytic performances of Pd-only TWCs slightly decreased, but the FTS catalyst still demonstrated higher catalytic performance and better thermal stability compared with the Pd-only catalysts prepared with single surfactant or without any surfactant. And the FTS catalyst has a wider 2 value （operation window） than other catalysts, even after being aged at 1000℃.

The effects of Chinese Yam-Epimedium mixture on respiratory function and quality of life in patients with chronic obstructive pulmonary disease

OBJECTIVE:To examine the clinical effects of a mixture of Chinese Yam and Epimedium in patients with stable moderate or severe chronic obstructive pulmonary disease(COPD).METHODS:Forty-nine patients with COPD were randomly allocated to a group whose usual treatment was supplemented with oral Chinese Yam-Epimedium mixture,or a control group given placebo.For each patient,body mass index,airflow obstruction,dyspnea,and exercise capacity were measured and converted into the BODE index before treatment and at one and three months after initiation of treatment.Participants also completed the St George's Respiratory Questionnaire(SGRQ) at the same intervals.RESULTS:After one month,improvements were seen in the BODE index and SGRQ of participants taking Chinese Yam-Epimedium mixture compared to controls.There were statistically significant differences in the SGRQ:three of its components and the total SGRQ scores were significantly decreased(P<0.05),respiratory symptom scores had improved(P<0.01),and the dyspnea component of the BODE index had significantly decreased(P<0.05).Similar improvements were observed after three months of treatment,but exercise tolerance had also improved:the six-minute walking distance had significantly increased(P<0.05) in the treatment group when compared with controls.CONCLUSION:Chinese Yam-Epimedium mixture can significantly improve dyspnea,exercise capacity,and the quality of life of patients with stable moderate or severe COPD.

Hollow mesoporous Ia3d silica nanospheres with single- unit-cell-thick shell： Spontaneous formation and drug delivery application

Mesoporous silica nanoparticles （MSNs） are promising for drug delivery and other biomedical applications owing to their excellent chemical stability and biocompatibility. For these applications, a hollow morphology with thin shell and open mesopores is preferred for MSNs in order to maximize the loading capacity of drugs. Herein we report a novel and direct synthesis of such an ideal drug delivery system in a dilute and alkaline solution of benzylcetyl- dimethylammonium chloride and diethylene glycol hexadecyl ether. The mixed surfactants can guide the formation of MSNs with cubic Ia3d mesostructure, and at a concentration of sodium hydroxide between 9.8 and 13.5 mM, hollow MSNs with uniform sizes of 90-120 nm and a single-unit-cell-thick shell are formed. A mechanism for the formation of the hollow Ia3d MSNs, designated as MMT-2, is proposed based on in situ small-angle X-ray scattering measurements and other analyses. MMT-2 exhibits much higher loading capacity of ibuprofen and degrades faster in simulated body fluid and phosphate buffered saline than non-hollow MSNs. The degradation of MMT-2 can be significantly retarded by modification with polyethylene glycol. More interestingly, the degradation of MMT-2 involves fragmentation instead of void formation, a phenomenon beneficial for their elimination. The results demonstrate the uniqueness of the hollow Ia3d MSNs and the great potential of the material for drug delivery and biomedical applications.

Calorimetry is not color-blind. Molecular insights on association processes in surfactant-polymer mixtures derived from calorimetric experiments

This comment will review and discuss recent results obtained with the use of calorimetry in assessing molecular information from complex phenomena such as association in surfactant/polymer mixtures. These examples were selected to support the view that it is possible to ally the great sensitivity of modem calorimeters with carefully planned experiments and, sometimes, ancillary techniques in order to derive detailed information on molecular interactions.