中巴资源卫星的矿化蚀变信息提取研究——以东天山沁城地区为例

本文利用东天山荒漠地区中巴资源卫星数据,通过掩膜处理,包括光谱角降低冲击物影响,动态阈值降低植被干扰,并对生成的基础图像用主成分分析法提取羟基异常,以标准离差σ作为遥感异常切割尺度进行异常分级。以前期ETM提取结果及东天山矿产地质图为检验源,经过对比分析,验证中巴资源卫星数据在找矿方面具有可行性。(重新修改了摘要)     

羟基杀灭船舶压载水微小生物中试实验研究

采用羟基处理压载水技术,使用羟基处理设备和管道作为模拟船舶排放压载水的管道。研究了羟基对海产小球藻、游仆虫和异养细菌的杀灭效果,说明羟基能有效杀灭压载水中的微小生物;并模拟船舶排放压载水过程中排放地的海水对处理后压载水的稀释作用,稀释后的水样经过96h的培养,没有发现微小生物复活的情况,证明了羟基杀灭船舶压载水微小生物在长度为4m(接触时间为2s)的接触管道内已经完成。并研究了羟基处理压载水技术对水质情况的影响,结果表明羟基有效杀灭船舶压载水微小生物的同时能改善压载水水质。     

影响羟基自由基在O3/UV体系中生成规律的因素

臭氧紫外光（O₃/UV）法是将臭氧与紫外光辐射相结合的一种高级氧化技术。在紫外光的辐射下臭氧显著地加速了分解速率,在溶液中形成具有强氧化特性的羟基自由基。通过高效液相色谱法和荧光检测器测定O₃/UV体系中羟基自由基攻击水杨酸的产物2,5-二羟基苯甲酸（2,5-DHBA）,从而间接测定了捕捉到的羟基自由基的量。结果表明,反应时间、水相温度、初始pH值的增加明显有利于羟基自由基的生成,紫外光波长的减小和水杨酸浓度的增加也会对生成羟基自由基的量产生积极的影响。     

菲对斜生栅藻(Scenedesmus obliquus)自由基的诱导及胁迫效应

通过静态模拟实验,研究不同浓度(0.005、0.01、0.025、0.05和0.1 mg/L)菲暴露96 h后,对斜生栅藻的生长、自由基含量、抗氧化系统以及脂质过氧化产物(MDA)的影响.结果表明,0.01 mg/L菲开始对藻细胞生长产生显著抑制作用,在此浓度下电子自旋共振检测到的自由基信号(g=2.0033,幅宽10.15 mT)显著增强;在浓度设置范围内,超氧化物酶歧化酶、过氧化物酶、谷胱甘肽-S-转移酶活性均被显著诱导,显示出抗氧化系统的应激机制.谷胱甘肽和MDA含量均在0.025 mg/L时被显著诱导.这说明斜生栅藻对菲暴露比较敏感,0.01 mg/L即已显示胁迫效应,自由基的诱导是斜生栅藻产生损伤的重要原因,藻细胞的生长量是比较敏感的损伤指标.     

Measurements of nighttime nitrate radical concentrations in the atmosphere by long-path differential optical absorption spectroscopy

The long-path differential optical absorption spectroscopy(LP-DOAS)technique was developed to mea- sure nighttime atmospheric nitrate radical(NO_3)concentrations.An optimized retrieval method,resulting in a small residual structure and low detection limits,was developed to retrieve NO_3.The time series of the NO_3 concentration were collected from 17 to 24 March,2006,where a nighttime average value of 15.8 ppt was observed.The interfering factors and errors are also discussed.These results indicate that the DOAS technique provides an essential tool for the quantification of NO_3 concentration and in the study of its effects upon nighttime chemistry.     

Hydroxyl Radical Concentrations Estimated from Measurements of Trichloroethylene during the EASE/ACSOE Campaign at Mace Head, Ireland during July 1996

During the EASE/OXICOA campaign of the NERC ACSOE programme, trichloroethylene and a wide range of man-made halocarbons and radiatively-active trace gases were monitored with high precision and high frequency throughout July 1996 at Mace Head on the Atlantic Ocean coast of Ireland. Trichloroethylene concentrations in concert with many other trace gases became elevated as regionally-polluted and photochemically-aged air masses reached Mace Head. However, as the anticyclonic air masses retreated during 19 and 20 July, trace gas concentrations remained elevated for a significant period. During this 2–4 day period, trichloroethylene concentrations decayed significantly, though the concentrations of the other more chemically-inert trace gases did not. A detailed interpretation of this behaviour using a Lagrangian dispersion model has allowed the estimation of average and peak OH radical concentrations of 3 and 9×10⁶ molecule cm^-3, respectively, during the travel from the source areas in the U.K. and the low countries out to Mace Head. Using a simple box model, the available Mace Head measurements, when combined into a detailed chemical mechanism, generated OH radical concentrations which peaked at 7×10⁶ molecule cm^-3, in close agreement with the estimates based on trichloroethylene decay.     

贻贝棘尾虫年轻与衰老无性系抗氧化能力的比较

贻贝棘尾虫采自黑龙江省帽儿山南山水库附近水塘,于１９９５年９月在本系实验室通过接合生殖得到的接合后体,克隆培养作为无性系;采用１９８８年９月以来实验室保存培养的去小核无性系为衰老无性系。     

Studies on free radical scavenging activity in Chinese seaweeds part I. Screening results

INTRODUCTIONIthaslongbeenknownthatfatsundergoslowautoxidationduringstorage;andthatantioxidantswhichscavengefreeradicalsexistingduringtheinitialstageorearlypropagationstageoflipidoxida tioncanpreventrancidity ,soantioxidantsareoftenusedasfoodadditivescapableofdelaying ,re tardingorpreventingtherancidityinlipidsduetooxidation .Inthissense ,anidealantioxidantshouldhavethefollowingcharacteristics:safeinuse ,noodor,flavororcolor,effectiveatlowcon centration ,easytoincorporateandavailableatlowco…     

Impact of halides on the photobleaching of dissolved organic matter

Understanding absorbance photobleaching of marine dissolved organic matter (DOM) is important because DOM chromophores impact oceanic primary productivity by affecting the depth of the photic zone, absorb UV radiation and affect ocean color used in remote sensing. However, the fundamental mechanisms which account for this bleaching are largely unknown. Controlled laboratory studies demonstrated that the presence of seawater concentrations of chloride and bromide ions enhanced absorbance photobleaching reaction rates by ~ 40%, regardless of DOM source or the presence or absence of carbonate ions. In contrast, halide ions generally did not affect fluorescence bleaching rates. Variations in ionic strength did not alter the enhancement in absorbance photobleaching by halide ions. Accordingly, the enhancement in absorbance photobleaching was specific to halide ions, rather than a generalized salinity effect. We confirmed the formation of hydroxyl radical (HO^•) in illuminated samples, and its significant scavenging in the presence of halide salts. Gamma-radiolysis experiments and associated modeling indicated that a small component (~ 12%) of the photobleaching enhancement by halides was consistent with the hypothesis that halide scavenging of HO^• will form reactive halogen radicals that target electron-rich chromophores within DOM more selectively than HO^•. The mechanism responsible for the major component of absorbance photobleaching rate enhancement by halides remains unresolved.     

The preparation and antioxidant activity of glucosamine sulfate

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O-2)/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfa...