Series Of Optimization Experiments Research Articles

Influence of oxygen pressure on the lattice constants of Ba0.6Sr0.4TiO3 thin films and preparation of BaTiO3/Ba0.6Sr0.4TiO3 superlattices

Using pulsed laser deposition (PLD) technology, BaTiO3 (BT) and Ba0.6Sr0.4TiO3 (BST) single-layer films were successfully prepared through a series of optimization experiments. X-ray diffraction investigations indicated that BT and BST thin films were nearly (001)-epitaxially grown on LaAlO3 (001) substrates. And functional relation between the lattice constants of BST thin films and the oxygen pressure was close to Boltzmann function from 10-3 to 25 Pa. Then the high-quality BT/BST superlattices were also prepared under these optimal conditions. The surface topography measurement by atomic force microscopy (AFM) demonstrated that the root-mean-square (RMS) roughness of BT/BST superlattice was only 0.3048 nm. The surface smoothness has achieved the atomic scale. In addition, satellite peaks were clearly observed in the XRD spectrum. According to the position of satellite peaks that belong to (002) diffraction peak, the superperiod of superlattices was calculated and the deposition rates of BT and BST thin films were deduced. Finally, laser induced thermoelectric voltage (LITV) effect was measured for the first time in BT/BST superlattices grown on vicinal-cut single crystal substrates, which was not found in BT and BST single-layer films.

ANALYSIS OF ACTIVE CONSTITUENTS IN RHIZOMA PICRORHIZAE BY CAPILLARY ZONE ELECTROPHORESIS

ABSTRACT An effective capillary zone electrophoresis (CZE) method has been developed for the determination of picroside II, cinnamic acid, ferulic acid, and vanillic acid in Rhizoma picrorhizae for the first time. After a series of optimization experiments, 100 mM borate buffer (pH 9.5), 30 kV applied voltage and 25°C temperature were selected. The contents of the four active constituents in crude drug, extracts, and capsule preparation of Rhizoma picrorhizae were successfully determined within 12 min, with gallic acid as internal standard, and the repeatability and recovery are satisfactory. In all samples, the content of picroside II is the highest, and can be regarded as the representative compound. The contents of picroside II were also determined by high performance liquid chromatography (HPLC), showing that the results by CE and by HPLC are comparable. The technological process of extract preparation containing different amounts of picroside II was investigated by CZE.

High-speed determination of aesculin and aesculetin inCortex fraxini by micellar electrokinetic chromatography

A new rapid micellar electrokinetic chromatographic (MEKC) method has been developed for the determination of two kinds of coumarin (aesculin and aesculetin) inCortex fraxini. After a series of optimization experiments, 100 mM boric acid (pH 9.5), 50 mM sodium dodecyl sulfate (SDS), 30 kV applied voltage and 35°C temperature were selected. The contents of aesculin and aesculetin inCortex fraxini were successfully determined within 6 min by this method with quercetin as internal standard. The relative standard deviations (RSD) of the method are 1,22% for aesculin and 1.02% for aesculetin on the basis of peak areas. The detection limits (3S/N) are 25 μg mL−1 for aesculin and 20 μg mL−1 for aesculetin. Calibration curves are linear in the concentration ranges of 136–1020 μg mL−1 for aesculin (r=0.9969) and 126–945 μg mL−1 for aesculetin (r=0.9993), and the recoveries are 98.5% for aesculin and 98.6% for aesculetin.

Fast determination of flavonoids in Glycyrrhizae radix by capillary zone electrophoresis

A fast capillary zone electrophoresis (CZE) method has been developed for the determination of four flavonoids (liquiritin, licoisoflavone A, licochalconel A and calycosin) in Glycyrrhizae radix. After a series of optimization experiments, 100 mM borate buffer (pH 10.5), 30 kV applied voltage and 35 °C temperature were selected. The contents of four flavonoids in cultivated and wild crude drugs of Glycyrrhizae radix with different growth periods from one to four years, collected from different areas were successfully determined within 8 min, with satisfactory repeatability and recovery.

Determination of harpagide and harpagoside inScrophularia ningpoensis by capillary electrophoresis

A simple, rapid, accurate and reproducible capillary electrophoresis method has been developed for the determination of two kinds of iridoid glycoside (harpagide and harpagoside) inScrophularia ningpoensis. After a series of optimization experiments, 0.05M borate buffer solution, pH 9.80, containing 10% methanol was selected. The content of harpagide and harpagoside in both the crude drug and the prepared pieces for decoction ofScrophularia ningpoensis were successfully determined within 10 min by this method.

Application Of Quasicrystalline Materials As Thermal Barriers In Aeronautics And Future Perspectives Of Use For These Materials

AbstractQuasicrystalline materials (QCs) have very interesting properties which make them good candidates to be used as coatings resistant to wear, high temperature oxidation, corrosion, etc. The potential application of AI71Co13Fe8Co8 (QC1), a quasicrystalline approximant alloy, as a thermal barrier coating (TBC) for components of aeronautical and power generation turbines was explored in our laboratories and the results are presented in this paper. QC1 is stable at I 1000°C and has a thermal conductivity similar to that of yttria stabilized zirconia (YSZ), the most commonly used material for TBCs. QC1 powders were low pressure plasma sprayed on IN100 superalloy and coatings of excellent quality were obtained after a series of optimization experiments. The “as deposited” coatings were characterized by XRD, SEM and TEM and the results indicated that the coatings retained the same microstructure and phase composition as the bulk material. However, when coated specimens were heat treated at 950°C, interdifussion between coating and substrate took place resulting in the transformation of the QC approximant phase. To avoid or retard this process, the effect of several diffussion barrier layers, deposited between substrate and coating, was studied and the results showed that some of these barriers were quite efficient in slowing the diffusion process. Extensive cyclic oxidation and hot corrosion studies were carried out, showing promising results for this new type of TBC coatings. A short term ground engine test was carried out with coated blades.

Development of random amplified polymorphic DNA markers for genetic mapping in Pacific yew (Taxusbrevifolia)

A genetic linkage map was constructed for Pacific yew (Taxusbrevifolia Nutt.) based on random amplified polymorphic DNA (RAPD) markers. A series of optimization experiments were conducted to develop a highly repeatable protocol for Pacific yew. In these experiments, a high MgCl2 concentration (5.5 mM) together with a low primer concentration (0.2 μm) in the polymerase chain reaction (PCR) mixture yielded the best amplification products. PCR amplification products were further improved by treating the template DNAs with RNase. Experiments showed that bovine serum albumine had the same effect as RNase on PCR amplification. The segregating mapping population consisted of 39 haploid megagametophytes from a single mother tree. DNA extracted from a subset of 6 megagametophytes was screened with 345 ten-base oligonucleotide primers of arbitrary sequence. Of the screened primers, 28% revealed at least one polymorphic locus. Eighty-six of these primers revealed at least one polymorphic locus and were used with the entire set of megagametophyte DNAs. One-hundred-two loci were scored and segregated in the expected 1:1 ratio (1.19 locus per primer). Linkage analysis was conducted using MAPMAKER. Forty-one of 102 markers were distributed into 17 linkage groups and covered 305.8 centimorgans. The remaining 61 unlinked markers should be assigned to linkage groups as more markers are added to the map.

Development of a direct radioimmunoassay for serum progesterone

A direct radioimmunoassay for the measurement of progesterone in human serum is described. Progesterone 11α-hemisuccinate was conjugated to tyrosine methyl ester (TME) by the mix anhydride method and then iodinated using chloramine-T. The radiochemical purity of different batches of125I-progesterone was greater than 95% and showed 70–75% binding with excess antibody. Progesterone 11α-hemisuccinate was coupled with BSA and injected to rabits. Antisera collected after three booster injections and having aK value of 1·1091/M was selected for the assay. Significant reduction in binding with antibody was seen when hormone free serum was used in the assay system. Various blocking agents were tried to reduce the serum effects and none of them were found satisfactory. From a series of optimization experiments, an assay was developed without the use of blocking agents. This assay used a much higher concentration of antibody along with lower amount of serum sample (50 μl). The optimized assay has a sensitivity of 0.5 nj/ml and a working range of 0.5 to 100 ng/ml. Serum samples were analyzed analysis showed good correlation between the results obtained from the present system and the DPC kit. (Y=0.93X+0.5,r=0.93, forn=25).