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1.
应用紫外–可见吸收光谱、三维荧光光谱对大沽排污河及大沽沙航道水体中有色溶解有机物(CDOM)的空间分布、组成、来源进行了分析.结果显示吸收系数a_(355)变化范围为1.73~23.62,m~(-1),CDOM丰度空间分布为大沽排污河下游最高,上游次之,大沽沙航道最低,表明大沽排污河下游水体有机污染负荷最大.CDOM荧光物质包括类蛋白质(T1、T2)和类腐殖质(A、C、M)两类组分,以类蛋白质组分的百分比最高,但相关性分析表明类腐殖质组分与CDOM的吸收相关性更好.A峰和C峰对应的最大发射波长及紫外–可见吸收光谱参数E253/203结果显示,大沽排污河下游水体CDOM芳香性较高,且芳香环取代基中含有较多的羟基、羰基、羧基、酯基.荧光指数HIXb显示大沽排污河下游水体CDOM来源以陆源输入(工业废水)为主,而排污河上游及航道水体CDOM主要由生物活动产生.  相似文献   

2.
有色溶解有机物质(CDOM)与非色素颗粒物质的吸收皆有随波长增高而类指数函数递减的特征,二者统称非色素物质吸收,其光谱斜率S是海洋水色遥感半分析算法中的一个重要参数.本文基于现场实测数据,比较3种获取该参数的拟合方法,结果表明,增加背景参数K的非线性方法能够有效校正长波段散射的影响,与利用自然对数-线性方法以及一般非线性方法(不含背景参数K)比较,R2的标准偏差(SD)小,受水体类型的影响小.这一结果对于半分析算法的发展具有应用价值.  相似文献   

3.
内陆水体(湖泊、水库、河流)在全球碳循环过程中起着重要作用,其中有色溶解有机物(CDOM)是内陆水体中溶解态有机物质,对水体的光学特性和生物地球化学过程具有重要的影响.由于受到时空变化和人类活动的影响,内陆水体的CDOM组分、来源与光学性质较为复杂.不同区域内或者同一研究区不同的水体类型,CDOM光学特性之间存在着较大差异,通常选取CDOM的吸收系数表征CDOM浓度,通过三维荧光光谱(EEM)表征CDOM荧光组分与来源.首先论述了CDOM的重要作用,并从文献计量学的角度分析了CDOM近20多年的研究进展;其次阐述了CDOM吸收与荧光特性的变化特征,进而分析CDOM荧光组分或者吸收系数变化的驱动因素,阐明了光化学作用与微生物作用对其组分与吸收的影响;最后根据CDOM与溶解有机碳(DOC)的关系,简述了遥感在估算内陆水体CDOM及DOC方面的作用,并讨论了CDOM研究的不足与展望.  相似文献   

4.
长江口有色溶解有机物光谱特性及其示踪溶解有机碳研究   总被引:1,自引:0,他引:1  
通过测定2014年2、3月份长江口表层水中有色溶解有机物(CDOM)吸收光谱及溶解有机碳(DOC)质量浓度,分析了CDOM吸收系数a330的水平分布、光谱斜率比(SR)和比紫外吸光度(SUVA254),探究了CDOM的来源及其与DOC的关系.研究表明:研究区域a330范围为0.45~3.10,m-1,平均值为(1.34±0.90)m-1.CDOM吸收光谱和DOC质量浓度与盐度均呈负相关性(R2=0.959,0,0.820,8),表明二者的来源都是以陆源为主,且二者的河口混合行均表现为保守混合.由SUVA254随盐度增大而减小得知,陆源CDOM相对于海源CDOM的芳香性较强.SR与盐度关系符合保守混合模型,说明研究区域的SR主要受物理作用影响.a330与DOC质量浓度呈正相关性(R2=0.852,5),表明CDOM可以作为DOC的示踪物质.  相似文献   

5.
鸡蛋样品用0.1mol/L Na2EDTA-Mcllvaine缓冲溶液溶解,离心后,上层清液用Oasis HLB固相萃取柱和羧酸型阴离子交换柱净化,用流动相洗脱定容后,用高效液相色谱紫外检测器在355nm测定,在0.010~0.500mg/kg范围,三个添加水平的回收率为90%~99%,变异系数小于13%,方法检出限为0.005mg/kg.  相似文献   

6.
为了设计在紫外波段消色差性能优良的三元复合λ/4波片,根据复合波片理论,利用同一波长(300nm)的2个λ0/4波片和1个λ0/2波片组合成复合波片,研究了复合波片的相位延迟量随波长的变化,得出复合波片在250-350nm的光谱范围内是消色差的;在此基础上对三元复合消色差λ/4波片进行了优化设计,即通过改变中间波片的相位延迟量和精确调整复合角,使消色差范围拓宽到200-400nm,相位延迟计算偏差在5%左右.通过改变中间波片的材料,即氟化镁晶体代替石英晶体,用上述同样方法设计出UVC波段消色差λ/4波片,其相位延迟计算偏差在2%以内.这种优化设计对拓宽紫外波段消色差范围,提高延迟量精度具有实用价值.  相似文献   

7.
文章利用纳木措水体中实测的辐射数据,即湖体在波长305nm、312nm和320nm的平均光谱漫衰减系数分别为O.39m6-l,0.40m^-1和O.34m^-1,光合有效辐射的平均漫衰减系数为0.14m^-1。初步分析了纳木措水体中紫外线和光合有效辐射的衰减特性。  相似文献   

8.
有色可溶有机物(CDOM)的分布及光学性质对于研究湖泊水体富营养化和水色遥感具有重要的科学意义.该文通过紫外分光光度法定量研究了2016年夏季鄱阳湖水体不同区域的有色可溶有机物光吸收特性,分析了aCDOM(440)与光谱斜率比值(S)的关系,讨论了CDOM吸收系数与藻类及其他环境因子之间的关系,并与其他湖泊和水库相比较.研究结果表明:鄱阳湖水体在440 nm波长处的吸收系数为0.13~2.17 m-1,均值为(0.93±0.54)m-1.不同区域的CDOM含量差异显著,排序依次为主航道>珠湖区>南矶山水域,表现为3种典型吸收光谱曲线.夏季在300~440nm波长处S与CDOM有很好的相关性.鄱阳湖CDOM分别来源于藻类降解、沉积物扰动和河流流入.珠湖区CDOM来源主要为内源性,由浮游植物降解所产生.南矶山水域CDOM来源于赣江等河流汇入以及养殖肥水排入,其吸收系数与水体总磷关系密切.  相似文献   

9.
用2,4-二羟基苯乙酮和氨基硫脲为原料,在微波辅助作用下固相合成了2,4-二羟基苯乙酮缩氨基硫脲,利用红外光谱及单晶X射线法对目标化合物进行了表征,该化合物为单斜晶系,空间群为C2/c,晶体学参数n=2.0900(2)nm,b=0.79290(8)nm,c=1.32481(14)nm;β=100.2090(10)°;F(000)=944,Z=8,V=2·1607(4)nm3,Dc=1.365g·cm^-3,Mr=225.27,最终结构偏离因子R=0.0460,Rw=0.1309,S=1.031,最终差值电子密度的最大值和最小值分别为401nm^-3。和-247nm^-3.  相似文献   

10.
甲磺酸帕珠沙星紫外光谱性质的研究及应用   总被引:1,自引:0,他引:1  
在0.1mol/L HCI介质中,甲磺酸帕珠沙星的紫外吸收最强且稳定,最大吸收峰在247nm处,另外在331nm处也有显著吸收.在247nm处,吸光度与药物质量浓度在0~30.0mg/L(R=0.99996)范围内呈线性关系,检测限为0.026mg/L,在331nm处,吸光度与药物质量浓度在0~90.0mg/L(R=0.99995)范围内呈线性关系,检测限为0.144mg/L.该方法操作简便快捷,灵敏度较高,体系稳定.用于合成样品中甲磺酸帕珠沙星的测定,结果满意.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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