Preliminary study on PAH degradation by bacteria from contami-nated sediments in Xiamen Western Sea, Fujian, China

In order to estimate the biodegradation of three polycyclic aromatic hydrocarbons (PAHs) compounds, bacterial strains were isolated from marine sediments in three heavily contaminated sites (Yuandang Lake, Dongdu Port and Aquacultural zones in Maluan Bay) in Xiamen Western Sea. The results show three bacterial strains, which used pyrene as the sole carbon source, were identified as strains of Aureobacterium sp., Arthrobacter sp., Rhodococcus sp. The PAH-degrading bacteria isolated had a strong ability to degrade phenan-hrene, fluoranthene and pyrene at different degradation rates. The highest degradation rate was observed when three PAH compounds were mixed with an individual strain in the medium. The three PAHs were degraded after one week with a degradation rate of 89.94 % for phenanthrene and 93.4 % for both of fluoranthene and pyrene. In addition, after 25 days of incubation, the degradation rate was 99.98 % for phenanthrene and 99.97 % for both of fluoranthene and pyrene. Optical density was measured to ..

AlGaAs／GaAsHBT的设计与研制

分析了A1GaAs／GaAsHBT的原理和材料结构，详细介绍了AlGaAs／GaAsHBT的器件结构及工艺流程，并对两方面进行了优化，研制出了特性较好的AlGaAs／GaAsHBT，其电流放大系数达到180，是目前国内报道的最高水平；开启电压小于0.3V

Screening, identification, optimization of culture condition and genome analysis of a bacterium with high ACE inhibitory activity

[Background] Lactobacillus is intestinal probiotics with the frequent observation of high angiotensin converting enzyme (ACE) inhibitory activity in its fermented milk. The marine is an optimal source for biological flora, including abundant types of Lactobacillus. [Objective] Lactobacillus resources were distributed in sediments of the Bohai Sea through the results of high-throughput sequencing. In order to exploit the sources for producing ACE inhibitory peptide and increase the ACE inhibitory activity in fermented milk of Lactobacillus, the present study was performed by using Lactobacillus helveticus GY-3 selected from sediments of the Bohai Sea. [Methods] Lactobacillus resources were detected by using high-throughput sequencing in sediments of the Bohai Sea. After the enrichment separation, 16S rRNA gene identification and genome sequencing analysis were then done on the selected strain. We also measured the ACE inhibitory activity of the fermented milk of the selected strain, and optimized the fermentation conditions of the selected strain through orthogonal test. [Results] Lactobacillus helveticus bacterium (GY-3) was identified and high ACE inhibitory activity was detected in its fermented milk. The optimal conditions for producing ACE inhibitory peptides by strain GY-3 are as follows: 37 &deg;C, 3% inoculation, and 1.0% glucose, 0.6% soy peptone, 1.0% yeast extract and 0.04% MnSO_4&middot;4H_2O in skim milk medium. The maximal ACE inhibitory activity could reach up to 79.52%. On the basis of genome sequence data of the bacterium, it was found that the ACE-inhibiting peptide were involved in the protease system, the polypeptide transport system and the peptidase system. [Conclusion] The present study provides a broader source and foundation for the development of lactic acid bacteria that are capable of producing ACE inhibitory peptide. Studying the genome lays a foundation for the study of biological characteristics and mechanism of ACE inhibition activity in the future. Additionally, this study is of great significance for the development of antihypertensive products.</p

利用常规工艺提高光子晶体GaNLED的出光效率

计算了GaN二维光子晶体的能带结构，并利用常规工艺在国内首次制备出了GaN基二维平板结构的光子晶体蓝光LED。经过器件测试表明，与没有制作光子晶体的器件相比，光子晶体使器件的有效出光效率达到了原来的1．5倍以上。另外，还对感应耦合等离子体刻蚀（ICP）的制备光子晶体LED的刻蚀工艺进行了分析

GaAs基光子晶体垂直腔面发射激光器

成功研制了光子晶体垂直腔面发射激光器，实现了连续电注入激射，工作波长为850nm，最小阈值为2mA，最大阈值为13．5mA，其中光子晶体的晶格常数在0．5～3μm范围，占空比在0.3～0．7范围．发现器件能否激射依赖于光子晶体参数，而激光器的阈值、出射功率、出射模式与光子晶体的晶格常数、占空比、缺陷大小等因素有关

光子晶体垂直腔面发射850nm波长激光器研究

文章报道了国内首次研制成功的光子晶体垂直腔面发射850nm波长激光器，实现了连续电注入激射．发现器件能否激射直接依赖于光子晶体结构参数，而激光器的阈值、输出功率、输出模式等与光子晶体的晶格常数、占空比、腔的大小等因素有关

Quantitative analysis of steels using PLS with three data reduction methods based on LIBS

Three methods, selecting characteristic lines of elements contained in the samples manually, selecting intensive spectral partitions manually and the whole spectra, were used to reduce dimensions of spectra of 27 steel samples acquired by Laser-Induced Breakdown Spectroscopy. The PLS models were built based on the data after dimension reduction to quantify the Mn concentration of samples. The results show that, PLS model built based on selecting intensive spectral partitions can achieve the best result with the least complexity and the highest generalization ability. Selecting intensive partitions is a promising solution to reduce dimensions for original spectra. &copy; (2014) Trans Tech Publications, Switzerland

Selection of spectral data for classification of steels using laser-induced breakdown spectroscopy

Principal component analysis (PCA) combined with artificial neural networks was used to classify the spectra of 27 steel samples acquired using laser-induced breakdown spectroscopy. Three methods of spectral data selection, selecting all the peak lines of the spectra, selecting intensive spectral partitions and the whole spectra, were utilized to compare the influence of different inputs of PCA on the classification of steels. Three intensive partitions were selected based on experience and prior knowledge to compare the classification, as the partitions can obtain the best results compared to all peak lines and the whole spectra. We also used two test data sets, mean spectra after being averaged and raw spectra without any pretreatment, to verify the results of the classification. The results of this comprehensive comparison show that a back propagation network trained using the principal components of appropriate, carefully selected spectral partitions can obtain the best results. A perfect result with 100% classification accuracy can be achieved using the intensive spectral partitions ranging of 357-367 nm