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聚硅酸金属盐絮凝剂的制备和絮凝性能 总被引:57,自引:2,他引:57
本文对制备聚硅酸金属盐絮凝剂的条件及其絮凝除浊除色效果进行了实验研究。结果表明,在适当酸化pH条件下,进行硅酸与金属离子聚合反应,可获得具有较高分子量的PSMS。低浓度PSMS可以保持较长稳定时间,与传统铝、铁盐凝聚剂相比,PSMS可显著提高并改善絮凝除浊除腐植酸的效果,这种PSMS絮凝剂更适合于水厂现场制备投加。 相似文献
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色楞金斯克制浆造纸厂位于距贝加尔湖60公里的色楞格河畔,年产17万吨未漂白纸浆,按照苏联政府1987年法令,该厂必须在1992年停止向色愣格河排放废水。本文讨论有助于使废水排放量减少90%(1989年减少到5000米~3/日 )和到1992年使水全部回收利用成为可能的途径。如本文所述在色愣金斯克使用的技术,包括固体废物利用技术,是向着使该厂在生态上适合于受特别保护的贝加尔湖集水盆地前进了一大步。色楞金斯克厂西伯利亚制浆造纸工程研究所的工作人员也许能帮助有兴趣的同行发展类似的技术。 相似文献
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宾冬梅 《湖南环境生物职业技术学院学报》2003,9(4):323-326
为加大对果子狸开发利用力度,满足人们生活需要,特进行果子狸胡萝卜肉丸子试制.试验表明:将果子狸肉用五倍清水漂洗三次,果子狸肉:肉=5:4,用盐量为3%,淀粉用量20%,胡萝卜用量12%,在10~15℃下擂溃30min,成型后在95~100℃下加热熟化20min即可得到味美、色佳、弹性良好的果子狸胡萝卜肉丸子制品。 相似文献
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白洋淀地区水中有机污染物的定性分析 总被引:15,自引:0,他引:15
本文通过液-液萃取,色-质谱联用技术,HP-5型石英毛细管对白洋淀地区三个有琐代表性的取样点水样进行了有机物定性分析,分离出几十种有机化合物,将化合物的种类,数量,相对大小进行比较,分析结果表明,白洋淀地区水样中,石油烃类及有毒有害有机物污染较严重,不同取样点中污染的浓度种类各不相同,水层较浅,人为搅动较大的地区水样中,有机物的种类及浓度表现明显增加,说明水体沉积物和陆地土壤中的颗粒对有机污染物有 相似文献
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《应用与环境生物学报》2019,(6)
为研究聚花野丁香(Leptodermis glomerata)的生物活性,综合利用多种色谱方法,对该植物95%乙醇提取物的化学成分进行了分离、纯化,从中共得到15个化合物.通过波谱数据分析及比对,将其分别鉴定为杨梅素(1)、(2R,3R)-二氢杨梅素(2)、槲皮素(3)、pinostrobin(4)、1,3-二甲氧基-2-羟基蒽醌(5)、2-甲氧基-1,3-二羟基蒽醌(6)、1,3,4-三甲氧基-2-羟基蒽醌(7)、1,2,3,4-四甲氧基蒽醌(8)、1,2,3-三甲氧基蒽醌(9)、5,7-二羟基色原酮(10)、3S-faramol(11)、(2R,4S)-catalponol(12)、(2S,4S)-catalponol(13)、3β-乙酰基齐墩果酸(14)、齐墩果酸(15).采用DPPH、ABTS、NO三种自由基清除活性测试模型,对上述化合物的抗氧化活性进行测试.结果表明,(2R,3R)-二氢杨梅素(2)、pinostrobin(4)和5,7-二羟基色原酮(10)表现出显著的自由基清除活性:当浓度为1 mg/mL时,化合物2对DPPH、NO自由基的清除率为91.2%、67.8%;当浓度为2 mg/mL时,化合物4对DPPH自由基的清除率为102.8%;当浓度为1mg/mL时,化合物10对ABTS、NO自由基的清除率分别为104.7%、95.7%.本研究表明聚花野丁香富含多羟基酚类化合物,其中部分化合物显示较强的抗氧化活性,具有开发利用价值.(图1表1参23) 相似文献
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欧阳慧 《湖南环境生物职业技术学院学报》2007,13(4):51-54
学会做人是中华民族优秀的文化传统,也是现代社会的普遍法则,中外一致,古今同理.本文从大学生学会做人的理论依据,学会做人的准则及如何做人三方面,阐述了如何做一个人人喜欢的对社会有用的人. 相似文献
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阐述了湘菜与糟制品的起源、发生、发展与特色,分析了国内外研究现状与发展趋势,通过借鉴传统糟制品生产工艺,将湘菜所特有的风味融入传统糟制品中,开发出适合大众口味的糟制湘菜,经济效益高,市场前景好. 相似文献
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Prediction of total bed material load for rivers in Malaysia: A case study of Langat,Muda and Kurau Rivers 总被引:1,自引:0,他引:1
Aminuddin Ab. Ghani H. Md. Azamathulla Chun Kiat Chang Nor Azazi Zakaria Zorkeflee Abu Hasan 《Environmental Fluid Mechanics》2011,11(3):307-318
A soft computational technique is applied to predict sediment loads in three Malaysian rivers. The feed forward-back propagated
(schemes) artificial neural network (ANNs) architecture is employed without any restriction to an extensive database compiled
from measurements in Langat, Muda, Kurau different rivers. The ANN method demonstrated a superior performance compared to
other traditional sediment-load methods. The coefficient of determination, 0.958 and the mean square error 0.0698 of the ANN
method are higher than those of the traditional method. The performance of the ANN method demonstrates its predictive capability
and the possibility of generalization of the modeling to nonlinear problems for river engineering applications. 相似文献
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Acetaldehyde is a naturally found chemical in food substances characterized by a fruity aroma at low levels. However, high levels of acetaldehyde can add to or change the taste of foods and beverages. More importantly, acetaldehyde has recently been found to be possibly carcinogenic to humans (Group 2B). In this investigation, the amounts of acetaldehyde in several alcoholic and non-alcoholic beverages consumed in Greece, including red or white wine, retsina, tsipouro, grappa, fruit-based liqueurs, beers with different alcohol content as well as mineral water, soft drinks, and fruit juices were measured. The analytical method used is based on derivatization of acetaldehyde with 2,4-dinitrophenylhydrazine and its subsequent measurement using high performance liquid chromatography. High concentrations (median, min–max) were detected in grappa (29.4, 29.2–52.7 mg L?1) and tsipouro (17.1, 0.8–55.6 mg L?1), followed by beer (6.8, 6.7–6.9 mg L?1) and red wine (3.7, 1.6–29.4 mg L?1); the lowest levels were detected in soft drinks (0.067, 0.033–0.075 mg L?1) and mineral water (0.04, 0.002--0.096 mg L?1). Levels of acetaldehyde in retsina were very high (68.1, 63.9--68.3 mg L?1) when after opening, the wine remained in plastic bottles for a long time, much higher than in samples taken from just opened bottles (7.2, 7.1–7.4 mg L?1). The amount of acetaldehyde shows some positive correlation to the alcoholic content. These results suggest that regulatory measures and consumer guidance may be necessary for acetaldehyde in beverages. 相似文献
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Floral nectar is offered by plants to animals as a reward for pollination. While nectar is typically a clear liquid containing sugar and trace amounts of amino acids, colored nectar has evolved in several plant families. Here we explore the functional significance of the phenolic compounds that impart a dark brown color to the nectar of the South African succulent shrub Aloe vryheidensis. Flowers of this aloe are visited for their nectar by a suite of short-billed birds that are occasional nectarivores, including bulbuls, white-eyes, rock thrushes, and chats. Dark-capped Bulbuls were more likely to probe model flowers containing dark nectar than those containing clear nectar, suggesting a potential signaling function for dark nectar. However, the main effect of the phenolics appears to be to repel "unwanted" nectarivores that find their bitter taste unpalatable. Nectar-feeding honey bees and sunbirds are morphologically mismatched for pollinating A. vryheidensis flowers and strongly reject its nectar. However, the frugivorous and insectivorous birds that effectively pollinate this aloe are seemingly unaffected by the nectar's bitter taste. Thus the dark phenolic component of the nectar appears to function as a floral filter by attracting some animals visually and deterring others by its taste. 相似文献
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Summary Of three common mouse species at the Mexican overwintering sites of the monarch butterfly, onlyPeromyscus melanotis eats monarchs. We hypothesized thatP. aztecus andReithrodontomys sumichrasti reject monarchs because they are more sensitive to the bitter taste and/or toxic effects of the cardiac glycosides (CGs) and pyrrolizidine alkaloids (PAs) in the butterflies. Two-choice preference tests revealed no difference in taste avoidance thresholds to free base and N-oxide forms of the PA, monocrotaline, but very different avoidance thresholds to the CG, digitoxin. Avoidance thresholds forR. sumichrasti andP. aztecus were, in respective order, 1020 and 34 times less than that forP. melanotis. We also tested the toxic sensitivity of juvenile mice by chronically feeding diets containing digitoxin or monocrotaline at concentrations similar to those used in the preference tests. No species developed CG toxicity, but bothP. melanotis andP. aztecus developed moderate PA toxicity (R. sumichrasti was not tested for PA toxicity).P. aztecus grew more slowly and manyP. melanotis had hepatic metabolic lesions. Thus, the three mouse species responded very differently to the taste and toxic properties of CGs and PAs at ecologically relevant concentrations: 1) CGs were taste rejected by all species exceptP. melanotis, while PAs were not; and 2) PAs were toxic, while CGs were not. 相似文献
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In this paper, a method using solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2-methylisoborneol (2-MIB), 2,4,6-trichloroanisole (TCA), 2-isopropyl-3-methoxy pyrazine (IPMP), 2-isobutyl-3-methoxy pyrazine (IBMP), and trans -1,10-dimethyl-trans -9-decalol (geosmin, GSM). The mass spectrometry was operated in selective ion monitoring (SIM) mode. Three kinds of SPE columns and three eluting solvents were compared, the C18 column was chosen as optimum SPE column, and methanol was chosen as the optimum eluting solvent. It was found that the method showed good linearity in the range of 1–200 ng·L-1 and gave detection limits of 0.5–1.5 ng·L-1 for individual compounds. Good recoveries (93.5%–108%) and relative standard deviations (1.58%–7.31%) were also obtained. Additionally, concentrations of these taste and odor compounds in Jinan’s surface and drinking water were analyzed by applying this method, and the results showed that GSM and 2-MIB were the dominant taste and odor compounds in Jinan’s raw water. 相似文献
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Rindy C. Anderson Stephen Nowicki William A. Searcy 《Behavioral ecology and sociobiology》2007,61(8):1267-1274
Low-amplitude “soft song” is used by a variety of songbirds; in some species during aggressive encounters, in others during
courtship, and yet others in both these contexts. In song sparrows (Melospiza melodia), soft song has thus far been observed only in aggressive encounters, where its production is a more reliable predictor of
attack than any other signaling behavior. We used song playback to test the response of both male and female song sparrows
to soft song. The design of the playback experiments took into account the existence of two classes of soft song: crystallized
soft song, which consists of song types also found in the broadcast repertoire, and warbled soft song, which consists of less-structured
song types not found in the broadcast repertoire. Female song sparrows responded with significantly less courtship display
to the playback of crystallized soft song than to that of normal broadcast song, and response to warbled soft song was if
anything lower than to that of crystallized soft song. Male song sparrows responded equally aggressively to normal broadcast
song as to crystallized soft song, and equally aggressively to warbled soft song as to crystallized soft song. The female
results support the conclusion that neither form of soft song functions in courtship. The male results suggest that the reliability
of soft song as a signal of aggressive intent is not maintained by a receiver retaliation rule. 相似文献
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Vineet Kumar Praveen Guleria Surinder Kumar Mehta 《Environmental Chemistry Letters》2017,15(2):165-177
Food toxins are produced as defense tools by microorganisms that use nutrients for their growth. Microorganisms thus spoil food, taste and can infect humans, sometimes leading to death. Food adulteration and brand protection are also major issues in the food industry. Here we review the use of nanomaterials for sensing food quality. Nanosensors can detect pathogenic bacteria, food-contaminating toxins, adulterant, vitamins, dyes, fertilizers, pesticides, taste and smell. Food freshness can be monitored using time–temperature and oxygen indicators. Product authenticity and brand protection can be assessed using invisible nanobarcodes. Overall, nanosensors with unique properties are improving food security. 相似文献
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Xiaoyan MA Shifei HU Hongyu WANG Jun LI Jing HUANG Yun ZHANG Weigang LU Qingsong LI 《Frontiers of Environmental Science & Engineering》2012,6(2):171-176
Metabolites of algae such as geosmin, 2-methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientific attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also discussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg·L-1 and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant k = 0.00213 L·(min·mg)-1. Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO4 dosage, but dramatically dropped with the increasing levels of humic acid (1.8–4.5 mg·L-1) and other odor-causing compounds (e.g. β -cyclocitral, 0–1886.0 μg·L-1). Solution pH (5.2–9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demonstrates that KMnO4 oxidation is an effective option to remove dimethyl trisulfide from water. 相似文献