Photoreaction of 2′-chloro-4-R-benzanilide: synthesis of 2-(4-R-phenyl)-1,3-benzoxazole and 9-R-phenanthridin-6(5H)-one (R=H, CH3, CH3O)

The UV photolysis of 2′-chloro-4-R-benzanilides in acetonitrile solution under nitrogen atmosphere leads to the formation of intramolecular photocyclization products (9-R-phenanthridin-6(5)-one, 20–30%), along with the minor photoreduction, photo-Fries, and intramolecular photosubstitution products. The photoreaction of 2′-chloro-4-R-benzanilide in acetonitrile solution containing 10% of water or aqueous sodium hydroxide however gives 2-(4-R-phenyl)-1,3-benzoxazole as a major product (30%) along with the photoreduction, photo-Fries and intramolecular photocyclization products.     

The photochemical reactions of the halogenated N-benzylanilines. Mechanism of the reactions

Several N-(2-halobenzyl)anilines and N-benzyl-2-haloanilines have been synthesized and their photochemical reactions studied. Upon irradiation, the aqueous acetonitrile solution of N-benzyl-2-chloroaniline was cyclized and reduced to give phenanthridine, 5,5′,6,6′-tetrahydro-6,6′-biphenanthridyl (THBP), N-ben-zylaniline, and bibenzyl. Similar products were produced in the photochemical reactions of other halo-genated N-benzylanilines, except iodo-substituted N-benzylanilines. No dimer (THBP) was produced from the iodo-substituted N-benzylanilines. Both singlet and triplet states are involved in the photochemical reactions of the haloarenes.     

Comparative study of three immunoassays based on monoclonal antibodies for detection of the pesticide parathion-methyl in real samples

Three immunoassay systems: indirect, direct competitive enzyme-linked immunosorbent assay (IC-ELISA and DC-ELISA), fluorescence polarization immunoassay (FPIA) based on monoclonal antibodies for the detection of parathion-methyl (PM) were developed and optimized. Several PM derivatives (haptens) were conjugated to proteins and fluoresceinthiocarbamyl ethylenediamine (EDF) to obtain immunogens and competitors. The influence of immunogen and competitor structures on the assay performance was investigated. IC-ELISA was the most sensitive of all techniques developed, with a detection limit of 0.08 ng ml⁻¹, but assay time was the longest (3.5 h per 96-well microtitre plate). DC-ELISA was easier to perform and quicker (1.5 h per 96-well microtitre plate) but less sensitive than IC-ELISA (detection limit was 0.5 ng ml⁻¹). FPIA was the fastest and simplest (7 min per 10 samples) but the least sensitive (detection limit was 15 ng ml⁻¹) technique. The methods were characterized by high specificity and reproducibility. The cross-reactivity for parathion-ethyl was around 30-40% for IC-ELISA and FPIA, but significantly higher (125%) for DC-ELISA. The immunoassays were applied to the analysis of PM residues in different food and environmental matrices. Methanol extracts of vegetable, fruit and soil samples were used for the analysis. Recoveries for most spiked samples averaged between 85 and 110%. The methods developed can be used for screening of food and environmental samples for PM residues without complicated clean-up.     

AN ACOUSTIC TRANSFORMER COMPOSED OF HORNS AND ITS APPLICATION

A new acoustic transformer was developed by connecting three horns to improve radiation performance in the frequency region below 500 Hz. The proposed acoustic transformer was evaluated by numerical analysis using the commercial computer program SYSNOISE and by experiment. The acoustic transformer is composed of three horns, one of which was used in an inverted form. A design model was developed by use of Webster's horn equation and showed that the transformer can improve radiation efficiency. This was confirmed by numerical calculation using SYSNOISE. An acoustic projector was designed by use of the developed transformer and a piezoelectric unimorph-type actuator. The sound pressure measured at the mouth of the constructed acoustic projector was compared with the sound pressures evaluated at the same location by numerical calculation to investigate the differences between the numerical simulation model and the actual acoustic projector. Sound pressures generated by several acoustic radiators were calculated numerically and compared with the measured and calculated sound pressures of the developed acoustic projector to evaluate the effects of use of the proposed acoustic transformer. The comparative evaluation shows that the proposed acoustic transformer can provide up to a 10 dB gain over use of a horn in the narrow band low-frequency region from 100 to 200 Hz.     

Platinum dendrites with controlled sizes for oxygen reduction reaction

Platinum dendrites were synthesized with the controlled sizes of 13–53 nm, and their electrocatalytic properties were evaluated for oxygen reduction reaction (ORR). Dendrites showed a superior activity for ORR and better selectivity for the production of H₂O, compared to commercial E-tek catalysts. Durability was also tested by estimating the change in electrochemically active surface area (ECSA) after extended periods of oxygen reduction. Dendrites with larger sizes showed improved durability.     

Sputter-deposited ZnO thin films consisting of nano-networks for binder-free dye-sensitized solar cells

ZnO nano-network structures with high porosity were prepared for use in the photoelectrodes of binder-free dye-sensitized solar cells (DSSCs) by DC sputtering and subsequent thermal oxidation. Zn thin films prepared at 100 °C showed nano-network structures with high porosity, while those prepared at 25 °C did not. This was partially attributed to the high mobility of sputter-deposited particles that arrived at the surface of the substrate and partially to a supersaturation mechanism. The prepared nano-network Zn was successfully transformed to ZnO without a morphological change via subsequent annealing in air. The power conversion efficiency of DSSCs based on the ZnO nano-network structures exhibited 10 times higher efficiency than those based on ZnO film prepared at 25 °C because of its large surface area for adsorption of dye molecules. The thickness of the ZnO nano-network structures increased linearly at 10 μm h^?1 as a function of sputter time. As the film thickness increased, the power conversion efficiency of DSSCs increased from 1.09% to 1.82%.     

Separation and Purification of Sesquiterpene Lactones from a Plant,Carpesium Triste var. Manshuricum KITAMURA

Carpesium triste var. manshuricum K. is a plant which is rarely distributed in Korea, and it has long been used as traditional medicinal herb for its antipyretic, analgesic, vermifugic, insectifuge,pain-relief,and antiinflammatory properties. Several sesquiterpene lactones were isolated from the genus Carpesium.     

用长气体靶研究22Na+α共振散射

在日本东京大学CRIB 次级束装置上,用长气体靶开展了22Na+ α共振散射的厚靶实验研究。针对长气体靶实验中的两体运动学重构问题,提出了一套包括构建空间复杂几何关系、计算能量损失以及反应运动学的逐事件分析方法;对22Na+α共振散射的实验数据进行了重构分析,得到了E_c.m. = 4.2 ~ 5.4 MeV 区间22Na( α,α ) 的激发函数,从实验的激发函数中观测到了复合核26Al 5 个较为明显的共振峰。鉴于26Al 共振态的衰变模式比较复杂,本工作发现的26Al新共振态的能级性质有待进一步的理论分析。The 22Na+α resonant scattering is studied via a conventional thick target inverse kinematic method with an extended gas target. A data analysis method is proposed for the two-body reaction kinematic reconstruction, in which the spatial geometry, the reaction kinematics and the energy losses are considered. The experimental data of 22Na+ αresonant scattering have been thus reconstructed, and the excitation function is obtained in the energy interval of Ec.m. =4.2~5.4 MeV. Five resonant states in 26Al are observed in the experimental excitation function. Since several decay modes coexist for the observed 26Al resonant states, multi-channel theoretical analysis is thus needed to reveal their structure and decay features.     

Mitigated membrane fouling in a vertical submerged membrane bioreactor (VSMBR)

In a laboratory-scale study, characteristics of membrane fouling in an A/O (anoxic/oxic) series membrane bioreactor (MBR) and in a vertical submerged membrane bioreactor (VSMBR) treating synthetic wastewater were compared under the same operating conditions. Accordingly, fouling characteristics of a pilot-scale VSMBR treating municipal wastewater were studied under various operating conditions. Various physical, chemical, and biological factors were used to describe membrane resistances. As a result, it was concluded that high concentrations of extracellular polymeric substances (EPS), high viscosity and a high sludge volume index (SVI) corresponded to high membrane resistance indicating severe membrane fouling in both the laboratory-scale MBRs and the pilot-scale VSMBR. In addition, high fouling potential was observed in the pilot-scale VSMBR at 60-day sludge retention time (SRT). In this case, as hydraulic retention time (HRT) decreased from 10 to 4 h, EPS concentrations increased and the average particle size increased, leading to reduced settling of the sludge and increased membrane fouling. To mitigate fouling, two different methods using air bubble jets were adopted in the pilot-scale VSMBR. As a result, it was found that air backwashing was more efficient for fouling mitigation than was air scouring.