The application of lightning forecasting based on surface electrostatic field observations and radar data

This paper presents an analysis of lightning forecasting based on atmospheric electrostatic field (EF), radar and lightning location data in Nanjing of China. The warning behavior with EF data in summer of 2009 was analyzed and the suitable EF warning indexes were determined. To improve EF warnings effect, a method of cloud-ground (CG) lightning nowcasting based on EF observations, radar data, etc. was proposed and the best radar forecasting index was selected in the paper. The experimental (2009) and independent test (2010) results show that POD is 82.7%, FAR is 14.6%, CSI is 72.4% and average lead time is 20.8 min.     

Effect of Rotation Rate on the Formation of Platinum-modified Polyaniline Film and Electrocatalytic Oxidation of Methanol

The oxidation of methanol was investigated on platinum-modified polyaniline electrode.Changes in the electrode rotation rates (Ω) during platinum electrodeposition remarkably affect the formation and distribution of platinum in the polymer matrix and consequently lead to different currents of methanol oxidation. The results show that platinum loading is proportional to rotation rates Ω^1/2.     

Spin and charge Nernst effect in a four-terminal double-dot interferometer

We investigate the spin and charge Nernst effect of a four-terminal Aharonov–Bohm interferometer with Rashba spin–orbit interaction (RSOI). It is shown that a pure spin Nernst effect or a fully spin-polarized Nernst effect can be obtained by modulating the magnetic flux phase ? and the RSOI induced phase φ. It is also demonstrated that some windows of ? (or φ) for maintaining an almost fully spin-polarized Nernst effect exist and their width is under the control of the other phase. Moreover, for the charge Nernst coefficient $N_c$ and spin Nernst coefficient $N_s$ the relationship $N_c(?,\phi )=?N_s(\phi ,?)$ always holds. These results suggest that our proposal may act as a controllable thermospin generator.     

The effect of surface microtopography of poly(dimethylsiloxane) on protein adsorption, platelet and cell adhesion

Chemical homogeneous poly(dimethylsiloxane) (PDMS) surface with dot-like protrusion pattern was used to investigate the individual effect of surface microtopography on protein adsorption and subsequent biological responses. Fibrinogen (Fg) and fibronectin (Fn) were chosen as model proteins due to their effect on platelet and cell adhesion, respectively. Fg labeled with ¹²⁵I and fluorescein isothiocyanate (FITC) was used to study its adsorption on flat and patterned surfaces. Patterned surface has a 46% increase in the adsorption of Fg when compared with flat surface. However, the surface area of the patterned surface was only 8% larger than that of the flat surface. Therefore, the increase in the surface area was not the only factor responsible for the increase in protein adsorption. Clear fluorescent pattern was visualized on patterned surface, indicating that adsorbed Fg regularly distributed and adsorbed most on the flanks and valleys of the protrusions. Such distribution and local enrichment of Fg presumably caused the specific location of platelets adhered from platelet-rich plasma (PRP) and flowing whole blood (FWB) on patterned surface. Furthermore, the different combination of surface topography and pre-adsorbed Fn could influence the adhesion of L929 cells. The flat surface with pre-adsorbed Fn was the optimum substrate while the virgin patterned surface was the poor substrate in terms of L929 cells spread.     

Add/drop channel filter based on two parallel long-period fiber gratings coupler

A wavelength-selective coupler constructed with two parallel long-period fiber gratings (LPFGs) was investigated thoroughly. Both the numerical and experimental results verified that the filter response could be improved by adjusting the UV refractive modulation of the gratings and by controlling the external surrounding. And an add/drop channel filter with high efficiency and good spectral characteristic was achieved even though the claddings of the two gratings were not processed. This feature is very favorable to simplify the fabrication process.     

Hydrogen Peroxide Sensor Based on Horseradish Peroxidase Combined with CaCO3 Microspheres and Gold Nanoparticles

Direct electrochemistry and electrocatalysis of horseradish peroxidase(HRP) were achieved by entrapping the enzyme between CaCO3 microspheres and gold nanoparticles through forming sandwich configuration (CaCO3-HRP-AuNPs). Polyanion, poly(styrene sulfonate)(PSS), was hybrid with CaCO3 microspheres to increase the surface negative charges for binding with HRP through electrostatic interaction. After the bioconjugate CaCO3 PSS-HRP was entrapped in chitosan based sol-gel(CS-GPTMS) film, HRP was encapsulated by in situ formation of an outer layer of AuNPs through electrochemical reduction of HAuCl4. The composite film containing AuNPs, CaCO3-PSS-HRP bioconjugates and CS-GPTMS can provide favorable microenvironment for HRP to perform direct electron transfer at glassy carbon electrode(GCE). HRP retained its bioelectrocatalytic activity and lead to sensitive and fast amperometric response for the determination of H2O2. H2O2 could be detected in a very wide linear range from 5.0×10–6 mol/L to 7.1×10–2 mol/L. The sandwich configuration of CaCO3-biomolecules-AuNPs could serve as a versatile platform for enzyme immobilization and biosensing.     

Direct evidence for hydrated protons as the active species in artificial photocatalytic water reduction into hydrogen

Photocatalytic water reduction to hydrogen over oxide semiconductors is one of the most extensively investigated artificial photocatalytic reactions, but the nature of the active species has not yet been elucidated. Here, we successfully prepared Pt/rutile TiO_2(110) surfaces with hydrated proton species via co-adsorption of hydrogen and water and observed the photocatalytic reduction of hydrated protons to H_2 upon UV light illumination. These results provide experimental evidence to prove hydrated protons as the active species for photocatalytic water reduction to hydrogen and demonstrate the occurrence of photocatalytic reduction of hydrated protons to H_2 within the H-bonding network on the catalyst surface instead of directly on the catalyst surface. The Pt-TiO_2 interface is capable of dissociating water to form hydroxyl groups that facilitate the formation of H-bonding network on the catalyst surface to enhance the photocatalytic H_2 production. Our results greatly advance fundamental understanding of artificial photocatalytic water reduction.     

High-performance thin-layer chromatographic analysis of selected organophosphorous pesticide residues in tea

The separation of 9 organophosphates (monocrotophos, quinalphos, triazophos, parathion-methyl, isofenphos-methyl, temephos, parathion, phoxim-ethyl, and chlorpyrifos) by high-performance thin-layer chromatography (HPTLC) with automated multiple development was studied. The HPTLC method was developed and validated for analysis of residues of phoxim-ethyl and chlorpyrifos in tea. The sample was extracted with acetonitrile and cleaned up by ENVI-CARB solid-phase extraction. The extract was directly applied as bands to glass-backed silica gel 60F254 HPTLC plates. The plates were developed with dichloromethane-hexane (1 + 1, v/v) in a glass twin-trough chamber. Evaluation of the developed HPTLC plates was performed densitometrically. The results indicated that the detection limits of phoxim and chlorpyrifos were 5.0 x 10(-9) and 1.0 x 10(-8) g, respectively. Recoveries of the pesticides from tea by this analytical method were 90.7-105.5%, and relative standard deviations were 7.3-13.5%. The precision and accuracy of the method were generally satisfactory for analysis of pesticide residues in tea.     

Development of a simple and stability-indicating RP-HPLC method for determining olanzapine and related impurities generated in the preparative process

A simple and stability-indicating reverse phase high performance liquid chromatographic (RP-HPLC) method was developed and validated for the determination of olanzapine (OLN) and related impurities in bulk drugs. Eight impurities were characterized respectively, and particularly a new process impurity from OLN synthesis was structurally confirmed as 1-(5-methylthionphen-2-yl)-1H-benzimidazol-2(3H)-one (Imp-7) by X-ray single crystal diffraction, MS, (1)H NMR, (13)C NMR and HSQC. A mechanism of formation pathway for Imp-7 was proposed. Optimum separation for OLN and eight related impurities was carried out on an Agilent Octyldecyl silica column (TC-C(18), 4.6 mm × 250 mm, 5 μm) using a gradient HPLC method. The method was validated with respect to specificity, linearity, accuracy, precision, LOD and LOQ. Regression analysis showed good correlation (r(2) > 0.9985) between the investigated component concentrations and their peak areas within the test ranges for OLN and eight impurities. The repeatability and intermediate precision, expressed as RSD, were less than 1.74%. The proposed stability-indicating method was suitable for routine quality control and drug analysis of OLN in bulk drugs.