Studies on porphyrin and phthalocyanine monolayers by means of compression-recompression isotherms and BAM

Monolayers of porphyrin and phthalocyanine at the air-water interface were studied by means of film balance and Brewster angle microscopy (BAM). Results showed that the final point of compression isotherm and that of recompression isotherm were coincident or not coincident depending on the target pressures. Results were discussed in terms of the morphology of monolayers observed by BAM.

Neural network retrieval of ocean surface parameters from SSM/I data

A new algorithm based on the multiparameter neural network is proposed to retrieve wind speed (WS), sea surface temperature (SST), sea surface air temperature, and relative humidity ( RH) simultaneously over the global oceans from Special Sensor Microwave Imager (SSM/I) observations. The retrieved geophysical parameters are used to estimate the surface latent heat flux and sensible heat flux using a bulk method over the global oceans. The neural network is trained and validated with the matchups of SSM/I overpasses and National Data Buoy Center buoys under both clear and cloudy weather conditions. In addition, the data acquired by the 85.5-GHz channels of SSM/I are used as the input variables of the neural network to improve its performance. The root-mean-square (rms) errors between the estimated WS, SST, sea surface air temperature, and RH from SSM/I observations and the buoy measurements are 1.48 m s(-1), 1.54 degrees C, 1.47 degrees C, and 7.85, respectively. The rms errors between the estimated latent and sensible heat fluxes from SSM/I observations and the Xisha Island ( in the South China Sea) measurements are 3.21 and 30.54 W m(-2), whereas those between the SSM/ I estimates and the buoy data are 4.9 and 37.85 W m(-2), respectively. Both of these errors ( those for WS, SST, and sea surface air temperature, in particular) are smaller than those by previous retrieval algorithms of SSM/ I observations over the global oceans. Unlike previous methods, the present algorithm is capable of producing near-real-time estimates of surface latent and sensible heat fluxes for the global oceans from SSM/I data.

Study on cytocompatibility of carboxymethyl-chitosan membranes to skin fibroblasts

Chitosan and carboxymethl-chitosan (CM-chitosan) membranes with different molecular mass were prepared by a casting method. The cytocompatibility of two kinds of polysaccharide membranes to skin fibroblasts that cultured in vitro were studied. The methods were to culture the cells in soaking fluid of membranes and to culture the cells on the membranes directly. The results showed that the soaking fluid had no toxicity to fibroblasts and the biological security of lower molecular mass membranes were better than higher molecular mass membranes, and CM-chitosan membranes were better than chitosan membranes. In addition, the growth of fibroblasts on chitosan membranes was inhibited and the cells would fall off from chitosan membranes after a period of culture. However, the cells adhered and expanded well on CM-chitosan membranes. All these demonstrated that cytocompatibility of CM-chitosan membranes to skin fibroblasts was better than chitosan membranes.

乌江流域沉积岩风化过程中稀土元素的富集与释放

以乌江流域石灰岩、白云质灰岩、白云岩、硅质岩、页岩和砂岩等沉积岩的13 条风化剖面为对象, 运用R 型分层聚类分析和质量平衡计算方法, 研究了这些岩石风化过程中稀土元素(REE) 的富集与释放及其对植物生长和河水REE 分布的影响, 目的是为河水物质来源研究和为农业生产提供依据。结果表明: (1) 乌江流域石灰土中REE 的富集程度显著高于各自母岩、黄壤、上陆壳(UCC) 、中国土壤(CS) 和世界土壤(WS) ; (2) 沉积岩风化过程中REE 的富集特征和机制可能与母岩中REE 分布特征以及风化剖面中有机质、铁(氢) 氧化物和粘土矿物的吸附有关; (3) 沉积岩风化过程中释放的REE 可为植物吸收利用; (4) 石灰岩等沉积岩风化过程中REE 和Fe 等元素的释放对河水溶解态REE 的分布有重要影响。

乌江流域沉积岩风化过程中铀的富集与释放

以乌江流域石灰岩、白云质灰岩、白云岩、硅质岩、黑色页岩和紫色砂岩等典型岩石的13 条风化剖面为对象,运用相关分析和质量平衡计算方法,研究了这些岩石风化过程中铀(U) 的富集与释放及其对河水U 分布的影响,旨在增进对U 生物地球化学循环的了解,也为流域U 污染防治提供依据. 结果表明, ①乌江流域风化物和土壤中U 的富集程度基本上高于上陆壳(upper continental crust , UCC) 、中国土壤(China soil , CS) 和世界土壤(world soil , WS) ; ②U 的富集和释放能力与母岩U 含量以及风化剖面中粘土矿物和铁氧化物/ 氢氧化物含量及吸附能力有关; ③石灰岩以及少量白云岩和碎屑岩风化过程中U 的释放对河水U 的分布特征具有重要的控制作用.

喀斯特流域风化成土作用及其矿质元素行为与环境质量

岩石风化成土作用是生态系统矿质元素的重要来源，也是全球矿质元素生物地球化学循环的重要环节。因此，岩石风化成土过程中矿质元素的行为与环境质量研究有助于我们深入了解矿质元素的生物地球化学循环及其生态环境效应，同时对农业生产和环境保护也具有重要意义。选择乌江流域沉积岩-土壤-植被-河流系统作为研究对象，采集了多个小流域盆地岩石、土壤、植物及溪水样品。通过测试样品的矿物、元素组成以及元素存在形态等，分析了喀斯特流域的矿物学与地球化学特征，研究了喀斯特流域的成土物源、风化成土方式及风化成土作用的控制因素，探讨了风化成土过程中矿质元素的行为与环境质量，为进一步进行喀斯特地区土壤-植被系统矿质元素的生物地球化学循环研究奠定基础，为喀斯特地区生态环境保护和修复以及稀土等矿质元素的农业利用提供科学依据，同时为核废料的地质处置提供参考。通过研究，取得了如下一些成果和认识： (1) 提出了弱淀积元素的概念，改进了侵蚀前后风化剖面中元素的演化模型。 (2) 硅酸盐岩地区土壤来源于下伏基岩的风化成土作用，其风化成土过程中存在脱硅富铝作用。 (3) 连续碳酸盐岩地区土壤最终来源于碳酸盐岩的风化成土作用，其风化成土作用存在四种方式和两个阶段。脱钙(镁)富铝硅和脱硅富铝两个阶段的研究结果，支持了王世杰等(1999)提出的碳酸盐岩两阶段风化成土模式。 (4) 岩性和地形是研究区风化成土作用的主要控制因素，植被和其它因素只是对其风化成土产物的理化性质进行了一些改造。 (5) 由于侵蚀、脱钙和元素本身的淀积作用，相对于研究区黄壤、中国土壤(CS)和世界土壤(WS)，研究区石灰土富集Mn、V、P、REE 和U 等矿质元素。风化成土过程中矿质元素的行为主要受岩性和地貌部位控制，还受元素性质、土壤pH 值、氧化还原条件、铁锰(氢)氧化物和有机质含量、粘土矿物组成以及植被条件等的影响。 (6) 石灰岩等岩石风化成土作用可以通过植物营养供给和元素相互作用影响土壤质量和植物生长。 (7) 石灰岩等岩石风化成土作用控制着溪水和乌江河流的pH 值以及Mg、Ca、P、Mn 和U 等矿质元素的分布特征。 (8) NH4Ac-HAc单一提取法可用于评价石灰土中Mg、Ca、K、Mn和P等多数矿质元素的植物可利用性。与何子平等(2001)的研究结果不同，石灰土中多数矿质营养元素对植物的供给能力高于其它土壤。

Partial oxidation of ethane to syngas in an oxygen-permeable membrane reactor

A perovskite-type oxide of Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCFO) with mixed electronic and oxygen ionic conductivity at high temperatures was used as an oxygen-permeable membrane. A tubular membrane of BSCFO made by extrusion method has been used in the membrane reactor to exclusively transport oxygen for the partial oxidation of ethane (POE) to syngas with catalyst of LiLaNiO/gamma-Al2O3 at temperatures of 800-900 degreesC. After only 30 min POE reaction in the membrane reactor, the oxygen permeation flux reached at 8.2 ml cm(-2) min(-1). After that, the oxygen permeation flux increased slowly and it took 12 h to reach at 11.0 ml cm(-2) min(-1). SEM and EDS analysis showed that Sr and Ba segregations occurred on the used membrane surface exposed to air while Co slightly enriched on the membrane surface exposed to ethane. The oxygen permeation flux increased with increasing of concentration of C2H6, which was attributed to increasing of the driving force resulting from the more reducing conditions produced with an increase of concentration of C2H6 in the feed gas. The tubular membrane reactor was successfully operated for POE reaction at 875 degreesC for more than 100 h without failure, with ethane conversion of similar to 100%, CO selectivity of >91% and oxygen permeation fluxes of 10-11 ml cm(-2) min(-1). (C) 2002 Elsevier Science B.V. All rights reserved.

Perovskite-type B-site Bi-doped ceramic membranes for oxygen separation

Novel mixed conducting oxides, B-site Bi-doped perovskites were exploited and synthesized. Cubic perovskite structures were formed for BaBi0.2COyFe0.8-yO3-delta (y less than or equal to 0.4) and BaBixCo0.2Fe0.8-xP3-delta (x=0.1-0.5) The materials exhibited considerable high oxygen permeability at high temperature. The oxygen permeation flux of BaBi0.2Co0.35Fe0.45O3-delta membrane reached about 0.77 x 10(-6) mol/cm(2) s under an air/helium oxygen partial pressure gradient at 900 degrees C, which was much higher than that of other bismuth-contained mixed conducting membranes. The permeation fluxes of the materials increased with the increase of cobalt content, but no apparent simple relationship was found with the bismuth content. The materials also demonstrated excellent reversibility of oxygen adsorption and desorption. Stable time-related oxygen permeation fluxes were found for BaBi0.2CO0.35Fe0.45O3-delta and BaBi0.3Co0.2Fe0.5O3-delta a membranes at 875 degrees C.

Application of CO2-TPD in the synthesis of composite oxides from metal-organic precursors

CO2-TPD was demonstrated an effective way to investigate the phase formation during pyrolysis for the preparation of composite oxides using metal-organic molecules as precursors. Based on the CO2-TPD results, it was found that calcination condition had deep effect on the carbonate formation and the minimum firing temperature to acquire pure phase composite oxide. An optimized calcination schedule was then developed.

Syngas production using an oxygen-permeating membrane reactor with cofeed of methane and carbon dioxide

CH4-CO2-O-2 reforming to syngas in a never Ba0.5Sr0.5Co0.8Fe0.2O3.delta oxygen-permeable membrane reactor using LiLaNiO/gamma-Al2O3 as catalyst was successfully reported. Excellent reaction performance was achieved with around 92% methane conversion efficiency, 95% CO2 conversion rate, and nearly 8.5mL/min.cm(2) oxygen permeation flux. In contrast to the oxygen permeation model with the presence of large concentration of CO2 (under such condition the oxygen permeation flux deteriorates with time), the oxygen permeation flux is really stable under the CH4CO2-O-2 reforming condition.

Easy fabrication of dense ceramic membrane for oxygen separation

A combined EDTA-citrate complexing method was developed for the easy preparation of mixed oxygen-ionic and electronic conducting dense ceramic membrane for oxygen separation. The nea method takes the advantage of lower calcination temperature for phase formation. lower membrane sintering temperature and higher relative density over the standard ceramic method.

Synthesis and gas permeation properties of an NaA zeolite membrane

A high quality NaA zeolite membrane, which shows a H-2/n-C4H10 permselectivity of 106, has been synthesized on a seeded alpha-Al2O3 support by a multistage synthesis method.