A novel numerical method for infinite domain potential problems

The infinite domain potential problems arise in many branches of scientific and engineering fields, which by now still pose a great challenge to scientific computing community.This study proposes a novel meshless singular boundary method (SBM) to solve infinite domain potential problems.The SBM is mathematically simple, easy-to-program, meshless and integration-free.To guar-antee the uniqueness of numerical solutions, this article adds a constant term into the SBM approximate representation.The effi-ciency ...     

Sedimentation processes and sedimentary characteristics of tidal bores along the north bank of the Qiantang Estuary

A tidal bore is a unique Earth surface process, characterized by its highly destructive energy, predictable periodicities and magni-tudes, and the production of characteristic sedimentary features. Tidal bores and associated rapid flood flows are highly turbulent flows of the upper-flow regime with a velocity over several meters per second. Reynolds (Re) and Froude (Fr) numbers, respectively, are larger than 104 and 1.0, making them significantly different from regular tidal flows but analogous to turbidity currents. Until now, understanding of tidal-bore depositional processes and products has been limited because of the difficulty and hazards involved with gauging tidal bores directly. The Qiantang bore is known as the largest breaking bore in the world. Field surveys were carried out in May 2010, along the north bank of the Qiantang Estuary to observe the occurrence of peak bores, including regular observations of current, water level and turbidity at the main channel. Several short cores were sampled on the intertidal flats to study the characteristic sedimentary features of tidal bores. Hydrodynamic and sedimentological studies show that the processes of sediment resuspension, transport and deposition are controlled primarily by the tidal bores, and the subsequent abruptly accelerated and decelerated flood flows, which only account for one tenth of each semidiurnal tidal cycle in the estuary. Tidal-bore deposits are generally poorly sorted because of rapid sedimentation after highly mixed suspension by intense turbulence. This behavior is characteristic of the absence of tractive-current depositional components in a C-M diagram. It also goes along with well-developed massive bedding, graded bedding, basal erosion structures, convolute bedding and dewatering structures. Together, these sedimentary features can constitute fingerprinting of turbidites, widely distributed in the deep-water environment. However, a tidal bore is triggered by intensely deformed tidal waves propagating into a shallow-water environment, which returns to regular tidal flows rapidly after the passage of the bore head. The tidal-bore deposits are usually bounded by the intertidal-flat deposits with typical tidal beddings at the top and on both flanks. The difference between tidal-bore deposits (TBD) and tidal sandy/muddy deposits (TSD/TMD) is evident not only in sedimentary structures, but also in the grain-size composition. They can be clearly distinguished in grain-size bivariate plots, typically the plot of mean grain size vs. standard deviation (or sorting). Some trend variations generally exist in mean grain size with TBD>TSD>TMD, sorting with TMD>TBD>TSD (larger value indicating poorer sorting), and both skewness and kurtosis with TSD>TBD>TMD. These findings will undoubtedly shed new light on our understanding of tidal-bore sedimentology, ancient tidal-bore sedimentary facies and environments, and related oil-and-gas field prospecting.     

全自热、非等压醇烷化替代铜洗工艺改造小结

氨合成系统运行压力高,吨氨气体单耗、综合能耗均偏高;铜洗系统存在物料消耗多、运行成本高;生产操作繁杂,易受外界因素干扰,经常出现出口气体CO、CO2微量跑高造成后工段氨合成触媒活性下降,严重时频繁造成合成系统切气;另外还经常出现铜洗塔起泡带液及设备跑、冒、滴、漏,成为生产的重要污染源,危害日益突出.     

Stabilization of Euler-Bernoulli beam with a nonlinear locally distributed feedback control

This paper studies the stabilization problem of uniform Euler-Bernoulli beam with a nonlinear locally distributed feedback control. By virtue of nonlinear semigroup theory, energy-perturbed approach and polynomial multiplier skill, the authors show that, corresponding to the different values of the parameters involved in the nonlinear locally distributed feedback control, the energy of the beam under the proposed feedback decays exponentially or in negative power of time t as t → ∞.     

A bioinformatic evaluation of potential allergenicity of 85 candidate genes in transgenic organisms

The potential of genetically modified organisms(GMOs) to increase allergenicity or predispositions to allergies has attracted much attention.An approach that will properly and holistically evaluate the allergenicity of GMOs is yet to be found.Here,85 transgenes that have been reported in both international and domestic studies during recent years are summarized case by case;49 of the transformed genes were from plant sources and 36 were from animal sources.EVALLERTM,a web server for the in silico assessment of potential protein allergenicity,was used to evaluate the potential of the transgenic proteins as allergens.The biomedical journals listed in Highwire(http://highwire.stanford.edu/) were searched and reviewed to decipher whether any of the transformed genes were linked to allergenicity or human health.The EVALLER analysis identified 5 allergenic genes,whilst our literature review found 11 genes that were either related to allergic cases or to clinical adverse events;all 16 of these genes have been used in GMOs.The analysis pathway that we have developed can help guide the selection of genes to be used in genetic modification.The pathway also provides a paradigm for allergenicity analysis of transgene candidates.     

团购行为模式及发展策略

文章对团购产生的原因与背景及团购参与各方的行为模式进行了深入分析，认为团购的产生和发展有其必然性，而制约团购发展的问题可归结为消费者逃遁、经营者犹犹豫豫和组织者机会主义行事等三个主要因素，需要从提高消费者和经营者的参与信心、建立消费者和经营者的约束与保护机制、建立具有长期稳定的参与者关系的团购模式等方面采取措施进行解决。     

Sequence analysis of the Microcystis aeruginosa FACHB-912 phytochrome gene supports positive selection in cyanobacteria

The phytochrome gene from Microcystis aeruginosa FACHB-912,isolated from algal blooms in Taihu Lake in China,was sequenced and found to code for a wavelength transition light receptor protein.The gene was composed of five distinct domains:a PAS fold domain,a GAF domain,a phytochrome domain,a His Kinase A(phosphoacceptor) domain,and a histidine kinase domain.Red-absorbing phytochrome,far-red-absorbing phytochrome,and photoconversion kinetics were monitored via the spectral characteristics of the protein.To detect positive selection,homologous sequences from cyanobacterium phytochrome genes were obtained from GenBank.Potential selective pressure was identified by phylogenetic analysis with maximum likelihood analyses.The frequency of the phytochrome gene being subjected to selective constraints suggests that positive selection is a potentially important mechanism that promotes the evolution of the cyanobacteria phytochrome gene.The sites identified in this study provide targets for further research on the structural-functional role of these residues,and on the correlation with the mechanism of algal blooms.     

Recognition and sensing of anions through synergistic effects using simple benzimidazolium-urea receptors

Benzimidazolium-based receptors 1-3 were designed and synthesized. On the basis of fluorescence, UV-Vis, and 1H NMR spectroscopic studies, and X-ray single crystal structure analysis, it was confirmed that the receptor 1 displays strong (C-H)+···X, N-H···X hydrogen bonds and charge-charge interactions with anions. More importantly, these investigations demonstrated that the charged (C-H)+ benzimidazolium and urea moieties play a synergistic role in anion recognition.     

多重微孔生物反应床填料选取的探讨

多重微孔颗粒生物反应床是我公司研究开发的一种经济且能强有效去除垃圾渗滤液中污染物的反应器。本文先对矿化垃圾填料和多重微孔颗粒填料的挂膜性能和粒径分布进行比较,再以上海老港垃圾填埋场调节池出水为研究对象,构建多重微孔颗粒反应床的小试模型,对比20℃条件下反应柱和多重微孔颗粒反应柱对COD、NH3-N、TN指标的去除效果。