优势降解菌-光照-铁矿粉联用对高浓度2,4,6-三氯苯酚废水的降解特性

研究了Bacillus cereus WTXJ1-16优势降解菌在不同降解时间、接种量、降解温度、初始pH和转速下对2,4,6-三氯苯酚(2,4,6-TCP)的降解特性,初步考察了优势降解菌-光照-铁矿粉联用下对2,4,6-TCP的降解效果。结果表明:浓度为10~8~10~9cfu/m L的WTXJ1-16菌株对初始浓度为100 mg/L的2,4,6-TCP废水的适宜降解条件是接种量为8%(体积分数)、37℃、初始pH 7.5、转速150 r/min和降解60 h。优势降解菌-光照-天然铁矿粉联用实验结果表明,有菌有矿组中光照和黑暗条件下的2,4,6-TCP降解率分别为68.6%和49.4%,比有菌无矿组高出10.3,6.3个百分点,比有矿无菌组高出了60.4,43.0个百分点,说明优势降解菌-光照-天然铁矿粉联用对高浓度2,4,6-TCP废水具有良好降解效果,光照和矿粉对WTXJ1-16优势降解菌具有协同促进作用。     

湿法脱硫石灰石制浆系统的比选

石灰石制浆系统被广泛应用于燃煤电厂石灰石／石膏湿法烟气脱硫系统中。对典型的湿磨制浆和石灰石粉制浆系统从工艺流程特点、设备组成、技术经济等方面进行详细的分析比较。考虑到1000MW机组工程石灰石耗量较大，从电厂长期运行角度考虑，推荐采用技术成熟、运行经济的石灰石湿磨制浆方案，同时要加强湿磨制浆系统的日常维护和管理：     

Evidence of Large-Scale Chronic Eutrophication in the Great Barrier Reef: Quantification of Chlorophyll a Thresholds for Sustaining Coral Reef Communities

Long-term monitoring data show that hard coral cover on the Great Barrier Reef (GBR) has reduced by >70 % over the past century. Although authorities and many marine scientists were in denial for many years, it is now widely accepted that this reduction is largely attributable to the chronic state of eutrophication that exists throughout most of the GBR. Some reefs in the far northern GBR where the annual mean chlorophyll a (Chl a) is in the lower range of the proposed Eutrophication Threshold Concentration for Chl a (~0.2–0.3 mg m⁻³) show little or no evidence of degradation over the past century. However, the available evidence suggests that coral diseases and the crown-of-thorns starfish will proliferate in such waters and hence the mandated eutrophication Trigger values for Chl a (~0.4–0.45 mg m⁻³) will need to be decreased to ~0.2 mg m⁻³ for sustaining coral reef communities.     

Identifying Reefs of Hope and Hopeful Actions: Contextualizing Environmental, Ecological, and Social Parameters to Respond Effectively to Climate Change

Abstract:  Priorities for conservation, management, and associated activities will differ based on the interplay between nearness of ecosystems to full recovery from a disturbance (pristineness), susceptibility to climate change (environmental susceptibility [ES]), and capacity of human communities to cope with and adapt to change (social adaptive capacity [AC]). We studied 24 human communities and adjacent coral reef ecosystems in 5 countries of the southwestern Indian Ocean. We used ecological measures of abundance and diversity of fishes and corals, estimated reef pristineness, and conducted socioeconomic household surveys to determine the AC of communities adjacent to selected coral reefs. We also used Web-based oceanographic and coral mortality data to predict each site's ES to climate warming. Coral reefs of Mauritius and eastern Madagascar had low ES and consequently were not predicted to be affected strongly by warm water, although these sites were differentiated by the AC of the human community. The higher AC in Mauritius may increase the chances for successful self-initiated recovery and protective management of reefs of this island. In contrast, Madagascar may require donor support to build AC as a prerequisite to preservation efforts. The Seychelles and Kenya had high ES, but their levels of AC and disturbance differed. The high AC in the Seychelles could be used to develop alternatives to dependence on coral reef resources and reduce the effects of climate change. Pristineness weighted toward measures of fish recovery was greatest for Kenya's marine protected areas; however, most protected areas in the region were far from pristine. Conservation priorities and actions with realistic chances for success require knowledge of where socioecological systems lie among the 3 axes of environment, ecology, and society.     

Effect of ultra-micro powder Dendrobium officinale on the molecular diversity of intestinal bacteria in mice with spleen-deficiency constipation北大核心CSCD

This research aimed to study the effect of ultra-micro powder Dendrobium officinale on the molecular diversity of intestinal bacteria in mice with spleen-deficiency constipation, in order to provide scientific basis for ultra-micro D. officinale therapy. The mice with spleen-deficiency constipation in treatment groups were respectively given the traditional decoction of D. officinale and 50% dose ultra-micro powder D. officinale. The metagenome DNA of intestinal flora was extracted from intestinal contents. Then ARDRA analysis was made after PCR by universal primer of bacteria. The results showed that OTUs, Shannon index and Brillouin index were the same between the normal group and the 50% dose ultra-micro powder group, and between the model group and the traditional decoction group, but greater in the former two groups than the latter ones. The similarity coefficient (0.500 0) was bigger between the 50% dose ultra-micro powder group and the normal group than between the model group and the traditional decoction group, which was 0.181 8. Both cluster analysis and principal components analysis showed that the molecular diversity of intestinal microbiotia in mice of 50% dose ultra-micro powder group was the closest to that in the normal group. The results showed that the weakened molecular diversity of intestinal bacteria in mice with spleen-deficiency constipation can be regulated by the two kinds of D. officinale treatments to different extent. The efficacy of 50% dose ultra-micro powder D. officinale is better than the traditional decoction.     

Numerical and experimental investigations on laser melting of stainless steel 316L metal powders

This paper presents numerical and experimental investigations on laser melting of SS grade 316L powder on top of AISI 316L substrate using a pulsed Nd:YAG laser. The objectives of the present study are to understand the effect of process parameters such as laser power, scanning speed and beam size on geometry characteristics of the melt zone and ball formation. We formulated a moving heat source problem and obtained transient temperature solutions using commercial finite element solver. The geometry characteristics of the melt zone are evaluated from the temperature solutions and compared with experimental results. The effect of laser parameters on the geometry, morphology and homogeneity of single track realization was methodically analyzed by utilizing characterization tools such as laser particle size analyzer, macro and microscopic inspection, Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The results presented in this paper are beneficial to realize homogenous layer formation in additive manufacturing processes involving powder melting by laser beam.     

γ-FeOOH-草酸系统中橙黄I的光化学脱色

以8W黑光灯为光源,γ-FeOOH为催化剂,加入草酸构成光化学Fenton体系,研究了这一体系中橙黄I的光化学脱色动力学;考察了橙黄I的初始浓度、初始pH值和草酸初始浓度对橙黄I光化学脱色降解的影响.结果表明,草酸能显著促进橙黄I的脱色与降解,橙黄I光化学脱色一级动力学常数随草酸浓度的增大呈先升后降的趋势,最佳草酸初始浓度为1·8mmol·L-1;溶液pH值的变化也显著影响橙黄I的脱色.光化学反应过程中Fe2+和总Fe的浓度也随草酸浓度与反应时间的变化而变化.     

活性粉末混凝土(RPC)的断裂力学性能

在试验及观察的基础上,对活性粉末混凝土的断裂过程进行定性分析,给出活性粉末混凝土的裂纹发展原理及钢纤维的增韧机理,并分析其不同于普通混凝土的两个基本断裂特征。介绍了利用缺口梁三点弯曲试验确定混凝土拉伸软化本构方程的方法。基于Hillerborg模型,提出活性粉末混凝土的拉伸软化模型,根据三点弯曲断裂试验结果,确定出活性粉末混凝土的双线性拉伸软化曲线中的具体参数。据该软化曲线公式,计算出的活性粉末混凝土断裂能同试验得出的值相比,误差仅为0.9%。笔者得出的双线性软化曲线能较精确地反映活性粉末混凝土材料的断裂特性,可为今后进行RPC裂缝的分析和预测提供定量计算的依据,对于研究活性粉末混凝土的断裂能、尺寸效应等问题也很具意义。     

短胶化、冲击好耐候粉末涂料用聚酯树脂的研究

介绍了偏苯三甲酸酐、三羟甲基丙烷等单体的用量对耐候聚酯树脂粉末涂料胶化时间的影响及l，6-己二醇、2-甲基-l，3-丙二醇等单体对提高耐候聚酯树脂粉末涂层低温抗冲击性能的作用。     

用新型絮凝剂处理制浆漂白废水

采用一种新型的有机无机复合型高分子絮凝剂(F-1)处理制浆漂白废水，进行了絮凝条件的优选试验和对比试验，结果表明：F-1絮凝剂的絮凝沉降效果与絮凝剂的用量、废水的pH有很大的关系。当废水的pH为6．0、絮凝剂用量为100mg／L时，漂白废水的色度、SS和COD的去除率分别为98．2％、93．6％和78．6％。而且，其絮凝性能明显优于阳离子聚丙烯酰胺(PAMC)、聚合氯化铝(PAC)以及聚合硫酸铁(PFS)等絮凝剂。