Photocatalytic performance of TiO<Subscript>2</Subscript> thin films connected with Cu micro-grid

Aiming at reducing the recombination of photo-induced carriers in semiconductor photocatalytic process, we prepared TiO₂ thin film with its surface modified by a connected Cu micro-grid via a microsphere lithography strategy, which showed higher photocatalytic activity than the pure TiO₂ film. The improvement of photocatalytic activity of Cu micro-grid to the TiO₂ film is due to the charge carrier separation and electron transfer by the conducting metal grid. The photocatalytic activity was improved as metal loading increased, which obtained the best performance at a certain loading amount, and then decreased at higher loading amount. This phenomenon was attributed to the metal’s bulk effect which could be explained by the relationship between the energetic positions and the metal cluster size. Supported by the National Natural Science Foundation of China (Grant Nos. 50672003, 50872005) and the National Basic Research Program of China (“973” Project) (Grant No. 2007CB613302) and the Fok Ying Tong Education Foundation (Grant No. 111050)     

Controlled amorphous crystallization: An easy way to make transparent nanoceramics

Fabrication of transparent nanoceramics is attracting more and more interests recently. In this study a new method of amorphous sintering followed by controlled crystallization (ASCC) was developed, and transparent LaAlO₃/t-ZrO₂ nanoceramic was prepared as an example. Based on a eutectic composition of Al₂O₃-La₂O₃-ZrO₂, glass powders were synthesized, sintered, and then converted to nanoceramics by post-heat-treatment. The heat-treatment performed at 1200 °C for 2 h produced a transparent LaAlO₃/t-ZrO₂ nanoceramic with an average grain size of 40 nm. Due to the nanoscale microstructure, the ceramic showed a transparency up to 55% at 800 nm (1 mm thick), Vickers hardness of 19.05 GPa, and fracture toughness of 2.64 MPa m^1/2, respectively.     

海带、鱿鱼复合海鲜营养酱的研制

本文介绍了一种以海带、鱿鱼为原料的复合海鲜营养酱的加工工艺,并对其工艺条件和质量指标进行了探讨。     

浅谈AOI系统在SMT生产线的应用实施

本文简要分析了SMT生产线上常用的检测方法,着重介绍先,进的全自动光学检测(AOI)技术及其优点,并提出配合SMT柔性生产模式的应用实施.最后重点介绍风华高科VPD系列在线式全自动光学检测机的功能.     

定时截尾数据最佳线性无偏估计方法

提出定时截尾数据最佳线性无偏估计方法.针对工程中常见的位置-尺度分布族,给出定时截尾情况下分布参数的最佳线性无偏点估计公式及其协方差矩阵,得到分布参数的置信区间、百分位值和百分率的点估计及其置信上、下限.详细讨论Weibull分布和对数正态分布定时截尾数据的最佳线性无偏估计问题.与目前工程中常用的极大似然估计(maximum likelihood estimation,MLE)方法相比,文中方法所得估计量不但在大样本而且在小样本情况下也具有最佳无偏性质,且计算简单、精度高,便于工程应用.     

Impact of inland pollution sources on the bacteriological water quality of the Southern Ganghwado Bay Area,South Korea

The bacteriological pollution of water is a serious global environmental issue. The pollution of water by human and animal wastes can be a source of hazardous pathogens, which may pose serious health risks. In this study, we evaluated the microbiological water quality in the southern Ganghwado Bay area, South Korea. A total of 30 samples (14 discharge water samples from the drainage area and 16 sea water samples from the adjacent area) were analyzed for the concentrations of total coliforms (TC) and fecal coliforms (FC) in November 2013. The highest concentration of FC (28,000 MPN/100 mL) was found at site L1 (inland). The highest mean concentrations of coliforms were found at sites W9 (sea water) and W11 (sea water), with TC and FC concentrations of 33 MPN/100 mL. In conclusion, site L1 located near W9 and W11 is clearly identified as the main source of pollution at Dongmak Beach.     

Microbial transformation of tectoridin from Pueraria flos by Lactobacillus and bifidobacteria

Tectoridin could be hydrolyzed to tectorigenin by β-glucosidase-producing intestinal bacteria. In this study, nine strains of Lactobacillus and bifidobacteria were screened for high levels of β-glucosidase activity. We investigated their ability to transform tectoridin from Pueraria flos to tectorigenin. Lactobacillus reuteri DSM20016 showed the highest cell-envelope associated β-glucosidase activity, whereas the intracellular β-glucosidase activity from Bifidobacterium adolescentis ATCC15703 was higher than the other screened bacterial strains. L. reuteri DSM20016, Lactobacillus rhamnosus GGB41031 and B. adolescentis ATCC15703 showed high bioconversion rate of tectoridin. L. reuteri DSM20016 showed the highest bioconversion efficiency of tectoridin, 100% tectoridin was hydrolyzed and there was an approximate 185-fold increase in the concentration of tectorigenin after 24 h. The present study suggests that L. reuteri DSM20016, L. rhamnosus GGB41031 and B. adolescentis ATCC15703 have great potential for converting tectoridin from Pueraria flos to more bioactive tectorigenin.     

Synthesis and photochromic properties of a multiple responsive diarylethene and its selective binding affinity for copper(II) ion

A multiple responsive photochromic diarylethene, 1-[2,5-dimethyl-3-thienyl]-2-[2-methyl-5-(2-pyridyl)-3-thienyl]perfluorocyclopentene (1) with excellent fatigue resistance has been successfully synthesized. Easy and reversible conversion is observed between the two open- and closed-ring isomers of 1 upon irradiation with UV and visible light. Addition of trifluoroacetic acid to these two isomers gives two new protonated products featuring distinctively different color changes. Photochromic diarylethene 1b is found to have selective interaction with copper(II) ion. With increasing amount of copper(II) ion, the absorption maximum of the photostationary state at 563 nm decreases and disappears eventually, and the color of the solution changes from purple to colorless. Upon UV light irradiation, the solution color remains colorless and can no longer be restored. UV-vis absorption spectroscopy, fluorescence, and NMR spectroscopy were used to investigate the selective interaction between diarylethene 1b and copper(II) ion with results indicating that diarylethene 1b exhibits selective binding affinity for copper(II) ion.     

Photo-degradation of methylene blue in the presence of 2-anthraquinone sulfonate and cyclohexanol

Hydroxyl radical is a highly reactive oxygen species and can be used to oxidize many pollutants and toxic organic compounds. 2-Anthraquinone sulfonate (2-AQS) was found capable of producing hydroxyl radicals under UVA exposure. In this study, the photo-induced oxidative degradation of methylene blue (MB) by 2-anthraquinone sulfonate was investigated. Results indicated that 2-anthraquinone sulfonate was able to photo-degrade methylene blue. Addition of some chemical such as cyclohexanol could significantly increase the photo-degradation of methylene blue by 2-anthraquinone sulfonate. The degradation process was investigated by using LC-MS. Potential photochemical reaction mechanism of 2-anthraquinone sulfonate was proposed in this paper. Influence of solution pH value and different ratios of 2-AQS, cyclohexanol and MB mixture on the degradation of methylene blue were also studied.