阳光纸业废水处理技术及应用

介绍了阳光纸业废纸造纸过程废水治理情况,简要介绍了厌氧、好氧反应原理及工艺控制关键点及存在的问题。     

A survey of total hydrocyanic acid content in ready-to-eat cassava-based chips obtained in the Australian market in 2008

Cassava (Manihot esculenta Crantz) is a widely consumed food in the tropics that naturally contains cyanogenic glycosides (cyanogens, mainly composed of linamarin, acetone cyanohydrin, and hydrocyanic acid). If cassava is not adequately processed to reduce the level of cyanogens prior to consumption, these compounds can lead to the formation of hydrocyanic acid in the gut. Exposure to hydrocyanic acid can cause symptoms ranging from vomiting and abdominal pain to coma and death. In 2008, a survey of ready-to-eat (RTE) cassava-based snack foods was undertaken to determine levels of cyanogens measured as total hydrocyanic acid. This survey was undertaken in response to the New South Wales Food Authority being alerted to the detection of elevated levels of cyanogens in an RTE cassava-based snack food. This survey took 374 samples of RTE cassava chips available in the Australian marketplace. Significant variation in the levels of total hydrocyanic acid were observed in the 317 samples testing positive for cyanogens, with levels ranging from 13 to 165 mg of HCN equivalents per kg (mean value, 64.2 mg of HCN eq/kg for positive samples). The results from this survey serve as a timely warning for manufacturers of RTE cassava chips and other cassava-based snack foods to ensure there is tight control over the levels of cyanogens in the cassava ingredient. Evidence from this survey contributed to an amendment to the Australia New Zealand Food Standards Code, which now prescribes a maximum level for hydrocyanic acid in RTE cassava chips of 10 mg of HCN eq/kg, which aligns with the Codex Alimentarius Commission international standard for edible cassava flour.     

Positron emission tomographic evidence of toxic effect of MDMA ("Ecstasy") on brain serotonin neurons in human beings

BACKGROUND: (+/-)3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") is a popular recreational drug that selectively damages brain serotonin (5-HT) neurons in animals at doses that closely approach those used by humans. We investigated the status of brain 5-HT neurons in MDMA users. METHODS: We enrolled 14 previous users of MDMA who were currently abstaining from use and 15 controls who had never used MDMA. We used positron emission tomography (PET) with the radioligand carbon-11-labelled McN-5652, which selectively labels the 5-HT transporter. We analysed whether there were differences in 5-HT transporter binding between abstinent MDMA users and participants in the control group. Blood and urine samples were taken and tested to check for abstinence. FINDINGS: MDMA users showed decreased global and regional brain 5-HT transporter binding compared with controls. Decreases in 5-HT transporter binding positively correlated with the extent of previous MDMA use. INTERPRETATION: Quantitative PET studies with a ligand selective for 5-HT transporters can be used to assess the status of 5-HT neurons in the living human brain. We show direct evidence of a decrease in a structural component of brain 5-HT neurons in human MDMA users.     

Electrostatic enhancement of diffusion-controlled protein-protein association: comparison of theory and experiment on barnase and barstar

The electrostatic enhancement of the association rate of barnase and barstar is calculated using a transition-state theory like expression and atomic-detail modeling of the protein molecules. This expression predicts that the rate enhancement is simply the average Boltzmann factor in the region of configurational space where association occurs instantaneously in the diffusion-controlled limit. Based on experimental evidence, this "transition state" is defined by configurations in which, relative to the stereospecifically bound complex, the two proteins are shifted apart by approximately 8 A (so a layer of water can be accommodated in the interface) and the two binding surfaces are rotated away by 0 degrees to 3 degrees. The values of the average Boltzmann factor, calculated by solving the Poisson-Boltzmann equation, for the wild-type complex and 16 complexes with single mutations are found to correlate well with experimental results for the electrostatic rate enhancement. The predicted rate enhancement is found to be somewhat insensitive to the precise definition of the transition state, due to the long-range nature of electrostatic interactions. The experimental ionic strength dependence of the rate enhancement is also reasonably reproduced.     

Development and application of C60-fullerene bound silica for solid-phase extraction of biomolecules

Sample pretreatment is the most important procedure to remove the matrix for interfacing with mass spectrometry (MS). Additionally, for the samples with low concentration, the process of preconcentration is required before MS analysis. We have newly developed a solid-phase extraction stationary phase based on C60-fullerene covalently bound to silica for purification of biomolecules of different characteristics. Silica particles of different porosity are modified with aminopropyl linker and then covalently bound to C60-fullerenoacetic acid or C60-epoxyfullerenes. The developed materials have been successfully applied as an alternative to commercially available reversed-phase materials for solid-phase extraction. C60-fullerene silica is able to retain small and hydrophilic molecules like phosphopeptides, which can be easily lost by reversed-phase sorbents. The novel materials are applied for desalting and preconcentration of proteins and peptides, especially phosphopeptides. In addition, the C60-fullerene silica is applied for the solid-phase extraction of selected flavonoids with recoveries of approximately 99%. The recoveries are compared with the commercially available solid-phase extraction materials.     

基于分层维的自由曲面反求建模技术研究

针对CMM测量数据的特点,提出了基于分层维的自由曲面建模技术,以分层维量作为分层依据进行数据分层,利用首尾判断法进行层内数据的排序,建立了大规模数据的拓扑关系.以此为前提, 研究并优化了NURBS求值快速算法,通过符号运算将B样条基函数描述为分段多项式的形式,通过分层维的设定来确定最小初始化数组,利用一个临时多项式存储中间计算结果,最终在大规模计算时进行的是多项式的求值,有效地加快了运算速度.经实例验证,本算法是准确可行的,满足工程实际需求.     

AZ91镁合金的应变疲劳行为研究

研究了铸态和挤压态AZ91镁合金的室温应变疲劳行为。结果表明,铸态镁合金表现为循环应变硬化,而挤压态镁合金可呈现循环应变硬化、软化或循环稳定。与此同时,对两种状态的AZ91镁合金的应变寿命行为和循环应力-应变行为进行了分析测试,确定了相应的室温应变疲劳参数。此外,利用扫描电子显微镜观察分析了铸态和挤压态AZ91镁合金的疲劳裂纹萌生和扩展行为。     

稀土元素Ce对热挤压变形Al-Mg合金组织与性能的影响

为了确定稀土元素Ce在Al-Mg系合金中的作用,向Al-4％Mg合金中加入不同含量的Ce,研究了Ce对合金显微组织和力学性能的影响。显微组织观察结果表明,加入0.3％～1．0％的Ce不仅可细化Al-4％Mg系合金的晶粒,同时也可改变合金中析出相的类型。拉伸试验结果表明,随着Ce的加入,挤压变形Al-4％Mg系金的室温抗拉强度和屈服强度均有所提高,其中当Ce的加入量为0．6％时,合金的强度最高,与未添加稀土元素的Al-4％Mg合金相比,可使抗拉强度提高近20％,屈服强度提高约16％。室温拉伸断口SEM分析结果表明,挤压变形Al-4％Mg系合金均表现出典型的韧性断裂特征。     

Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facility

The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.     

逆向工程实体模型重建技术研究

针对CMM扫描线数据,进行了数据分层和数据排序,完成了数据拓扑关系的建立.研究了距离阈值法和向量角度法相结合的数据精简方法和基于分层维的特征提取技术.以基于分层维的数据处理技术研究为基础,提出了一种利用数据点特征的非均匀有理B样条(NURBS)曲面重构方法,在Solidworks中实现了实体模型的重建.