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1.
氨基酸分子首次用以制备构筑稀土介孔发光材料.L-丝氨酸通过分子修饰得到新配体2-烟酰氨基-3-羟基丙酸(L),并进一步引入MCM-41介孔基质中,最后和稀土Tb3+离子复合得发光介孔材料Tb-L-MCM-41.通过核磁共振、紫外、XRD、氮吸附和荧光光谱等对配体和杂化材料的结构和性质进行了表征.结果表明,配体L很好的引入到MCM-41介孔基质中,Tb-L-MCM-41介孔材料呈现L的特征紫外吸收.同时,稀土配合物的引入占据了MCM41基质的部分孔道,使其比表面和孔体积都有所降度.Tb-L-MCM-41呈现稀土Tb3+离子的特征光.  相似文献   

2.
瑶医药与中医药同源于伏羲神农,奠基于春秋诸子百家.两者具有相同的传统文化核心,如出一辙的思维模式,只是在秦汉之后,瑶医药与中医药出现明显分野,尤其是药学体系差异颇大.虽然在盛世太平年代,汉、瑶医药学也有交叉融合,但最终形成了不同于中医药的理论与实践体系,为中国民族医药学的繁荣发展做出了贡献.  相似文献   

3.
研究以超高效液相色谱—三重四级杆串联质谱联用技术(UPLC-MS/MS)测定陈皮中T-2毒素含量的方法.陈皮用乙腈-0.1%甲酸溶液提取,经PSA(乙二胺-N-丙基硅烷)净化,LCMS/MS电喷雾正离子多反应监测(MRM)模式检测.T-2毒素在1~25μg.L-1的浓度范围内进样量与峰面积呈良好的线性关系(r=0.9996),陈皮中T-2毒素的检测限为2.0μg.kg-1.平均加样回收均为91.86%,RSD为2.88%(n=9).该法操作简便,结果准确,可作为陈皮中T-2毒素残留量检测方法.  相似文献   

4.
马铃薯与甜瓜、糯玉米、大白菜、茼蒿及冬青菜的间套种,是笔者近年试验探索成功的又一理想的多熟立体高效复种模式.我县示范推广的3公顷复种田,每亩年均产值11500元以上(马铃薯1600kg×1.2元、甜瓜1750kg×1.4元、糯玉米鲜穗500kg×2元、大白菜2000kg×1.2元、茼蒿1400kg×1.4元、冬青菜1500kg×1.2元),扣除成本1500元.净产值逾1万元,经济、社会效益极为显著.其复种要点如下.  相似文献   

5.
开方术是中国传统数学中发展较为完善和成熟的内容之一,最早见于《九章算术》和《少广》章.后经宋元发展为“立成释锁”和“增乘开方”算法,是一种解决一元高次方程的一个正实数根的有效方法.不知是巧合还是人为抑或是算法本身的局限,中国古代的高次方程几乎都只有一个正根;而两个正根的方程作为不和谐的声音表现为赵爽二次方程求解的隐喻,刘益、杨辉的视而不见和秦九韶、李冶的不选之择.直到汪莱指出对秦九韶和李冶“不可知为可知”的错误,多正根的方程即“不可知”才进入算家的视野.李锐以前对于有多个正根的方程没有有效的解决方法.为此,李锐给出新的步法,用“代开法”求出多个正根.而就多个正根的方程而言,用基于新步法的“正负开方术”是求解方便且计算效率高的方法.  相似文献   

6.
本文在室温固相化学反应法的基础上使用了表面活性剂,使合面条件降低,合成方法完善.在温和的条件下,制备出了粒度小于100纳米的硫化镉、硫化锌、硫化汞、氧化汞.  相似文献   

7.
王清 《山东科学》1991,4(1):50-54
本文提出了测定结晶硅中六个杂质元素的光谱定量分析方法,阐述了整个分析方法的详细过程.分析结果的相对误差为±6.7及—13.3%;回收率为86~106%.  相似文献   

8.
成都市近郊蔬菜地土壤Cd,Cu,Ni,Pb,Zn的污染评价   总被引:1,自引:0,他引:1  
本研究选择成都市近郊蔬菜地采集表层(0~20cm)和底层(20cm)土壤样品,分析土壤中重金属(Cd,Cu,Ni,Pb,Zn)及其可交换态的质量分数,并利用单因子污染指数(Pi)、综合污染指数(P综合)、风险评价编码法(RAC)和Hakanson潜在生态风险指数法(R_I)评价重金属的污染程度和潜在生态风险水平.结果表明,表层和底层土壤中重金属质量分数差异没有统计学意义,均明显高于四川省土壤背景值,但低于国家土壤环境质量二级标准.表层土壤中可交换态重金属的质量分数高于底层.表层土壤中重金属整体上呈中等污染,而底层土壤呈轻度污染.RAC的结果表明土壤中Cd具有较高的迁移性,呈现出明显的潜在生态风险,Cu,Ni,Pb,Zn处于低风险水平.表层和底层土壤中重金属的潜在生态风险均表现为轻微风险水平.研究结果表明,成都近郊蔬菜地土壤重金属的污染和风险较高的区域主要分布于双流区和郫都区,较低区域主要分布于龙泉驿区.Cd是研究区需要进一步关注的重金属.  相似文献   

9.
International Conference on Plant Molecular Breeding (ICPMB) will be held in Sanyacity, Hainan Province, P. R. China, on October 27-30, 2005. The conference is sponsoredby China Agricultural Society, and co-hosted by Hainan Institute of Tropical AgriculturalResources (HITAR) and Hainan Provincial Key Lab for Crop Molecular Breeding. It is amultidisciplinary conference that brought together academic and industrial scientists fromPlant germplasm, Plant genomics, Transge…  相似文献   

10.
Gold nanoparticles were assembled with the rigid cross-linker, H10TTPR. The assembly process was studied with the UV-vis spectroscopy and TEM. By adjusting the amount of H10TTPR added to the gold nanoparticle solution,the aggregate form of gold nanoparticles could be controlled.  相似文献   

11.
TheLowerCambrianblackshalesequenceoccursinSouthChinaalonganarc parallellinearbeltex tendingmorethan 16 0 0km .Theseorganic richblackshalesformedinvariousmarineenvironmentsandtypicallycontainhigheramountsofmolybdenum ,nickel,vanadium ,andanumberofothereconomical lyimportantmetalsthandoanyothersedimentaryrocks[1,2 ] .Therefore ,thestudyoftheseblackshaleshasnotonlypaleoceangraphicimplicationbutalsoe conomicsignificance .Marinesedimentssuchasblackshalearecom plexmixturesofdetritalphasesandseawat…  相似文献   

12.
 对南兴安岭地区晚中生代火山岩的Pb同位素进行了分析,结合其主微量元素和Sr-Nd同位素地球化学特征,探讨了火山岩的岩石成因。满克头鄂博组低钾拉斑-钙碱性玄武安山岩表现出富集LILE、LREE和HFSE亏损元素地球化学特征以及稍高放射性成因Sr、Pb (87Sr/86Sr=0.704 88~0.704 99; 206Pb/204Pb=18.18~18.23)和弱相对亏损至弱富集的Nd同位素组成(εNd((t)=-0.12~+0.68),其来源于俯冲沉积物参与改造富集地幔熔融源区。该组的英安岩-流纹岩较基性岩浆具有稍高放射性成因Sr、Pb (87Sr/86Sr=0.705 22~0.707 09; 206Pb/204Pb=18.16~18.33)和低Nd同位素组成 (εNd(t))=-1.5~-0.4), 且在空间上与玄武岩共生,为玄武质岩浆结晶分异,并同化混染作用 (AFC)的产物。玛尼吐组英安岩具有与现代俯冲带adakite岩石相似的特征;在Sr-Nd-Pb同位素组成上,它们较同期或近期玄武安山岩更低Sr、Pb (87Sr/86Sr=0.704 09~0.704 25;206Pb/204Pb=18.15~18.17)和高Nd同位素比值(εNd((t))=+0.9~+2.1),为造山带下地壳镁铁质岩石的部分熔融产物。  相似文献   

13.
The Pb, Sr isotopic compositions in organic matters (kerogen and soluble organic matter) of Lower Tertiary hydrocarbon source rock in Liaohe Fault Depression is first reported. There is a great variable rang of Pb isotopic compositions in kerogen, 206Pb/204Pb = 17.488-18.656, 207Pb/204Pb= 15.388-15.692, 208Pb/204Pb = 37.656-37.484. And soluble organic matters have a very stable Pb isotopic composition, that is 206Pb/204Pb = 17.424-17.601, 207pb/204pb= 15.376-15.448, 208Pb/204Pb = 37.620-37.870. Sr isotopic composition varies in the range of 0.747 59-0.716 79 in kerogen and of 0.709 67-0.747 59 in soluble organic matters that have a great range. It is shown that mantle fluid can influence organic matters and make them form hydrothermal hydrocarbon in the geoglogic environment of rift basin.  相似文献   

14.
A SHRIMP U-Pb zircon geochronology study of the tuff at the bottom of the Lower Cambrian Niutitang Formation at Songlin, Zunyi, South China yielded a mean ^206Pb/^238U age of 518±5 Ma. It is significantly younger than the Re-Os ages of 537--542 Ma for the overlying polymetallic Ni-Mo-PGE-rich layer in the basal Niutitang Formation at Songlin, suggesting that the Re-Os ages might represent that of the original magma chamber for the Ni-Mo-PGE-rich layer rather than the formation age of the strata. The intra-basinal stratigraphic correlation also implies that the absolute age of the Chengjiang biota should be younger than 518±5 Ma. Our new result, together with the SHRIMP U-Pb zircon age for the K-bentonite in the Zhongyicun member of the Zhujiaqing Formation at the Meishucun section, Yunnan Province, provides a temporal constraint for the Lower Cambrian of the Yangtze Platform in South China.  相似文献   

15.
The paleo oceanenvironmentalchangeduringthePrecambrian Cambriantransitionisakeyissuere latedtothecausesforanexplosiveradiationofdiffer entmetazoanphyladuringtheEarlyCambrianera .Thechemicalandisotopiccompositionsofmarinesed iments (carbonates ,phosphorites ,siliceousrocks ,andblackshales)recordthechangingcompositionandphysicalconditionsoftheseawaterinwhichtheserocksaccumulated .Organiccarbon richblackshalesfrommarineenvironmentsarecommonlyenrichedinanumberoftraceelementssuchasNi,Mo ,V ,Co ,…  相似文献   

16.
Profound geotectonic, climatic and biological changes occur during the terminal Neoproterozoic and its transition into the early Cambrian. These are reflected in temporal variations of the chemical and isotopic composition of seawater. We are studying a sequence of sedimentary rocks at the Shatan section, northern Yangtze Platform, Sichuan Province of China. This succession comprises, in ascending stratigraphic order, predominantly calcareous sediments of the Sinian upper Dengying Formation and black shales of the lower Cambrian Guojiaba Formation (time equivalent of Niutitang Fm.). Paleoenvironmental setting represents shallow-water shelf deposits. The objective of our study is to provide temporal records for the isotopic compositions of organic and carbonate carbon throughout this time interval. Organic carbon isotope values display a range between -35.8‰ and -30.1‰ with clear stratigraphic variations. Carbonate carbon isotope data vary between -3.5‰ and +0.5‰. These secular variations are interpreted to reflect perturbations of the global carbon cycle, specifically changes in the fractional burial of organic carbon. However, local conditions have further affected the isotopic signals.  相似文献   

17.
内蒙古四子王旗地区出露的早白垩世玄武岩属于钾玄岩。岩石富集大离子亲石元素(LILE)、轻稀土元素(LREE),亏损高场强元素(HFSE),其地球化学特征总体与洋岛玄武岩(OIB)相似。w(Rb)/w(Nb)、w(K)/w(Nb)、w(Zr)/w(Nb)、w(Th)/w(Nb)和w(Th)/w(La)比值主要落在EM1-OIB范围内。w(206Pb)/w(204Pb)、w(207Pb)/w(204Pb)和w(208Pb)/w(204Pb)分别变化在17.18~17.81, 15.40~15.50和37.54~38.05之间,岩石的Pb同位素组成接近EM1型地幔端元。随着Pb含量(质量分数)的增加,Pb同位素比值几乎没有变化,表明四子王旗钾玄岩没有经历明显的地壳物质混染。钾玄质母岩浆源于软流圈地幔的减压低度部分熔融。四子王旗钾玄岩是华北克拉通岩石圈减薄事件的产物。  相似文献   

18.
Samples of black rock series collected from the Lower Cambrian Niutitang Formation, northwestern Hunan Province, China, were analyzed for trace elements.The trace element geochemical characteristics of the ore layer (high enrichments of Ni, Mo, V, U, Cu, Pb, Zn, Cd, Tl and Ba; high U/Th ratios and LREE-enriched patterns with positive Eu and Y anomalies) support the assumption that the Ni-Mo polymetallic layer is of submarine hydrothermal origin.High field strength elements (HFSE) and lithophile elements such as Nb, Ta, Zr, Hf, Li, Be, Rb, Cs, Th and Sc are remarkably higher in the upper unit than those in the lower unit of the Niutitang Formation.These features may reflect that hydrothermal contributions were diminished, and terrigenous constituents were increased in the sediments of the upper unit of the Niutitang Formation.  相似文献   

19.
The spatial distribution and environmental significance of Pb and its stable isotope ratios in central Arctic snow are discussed. The shear zone is a dividing line. The concentration of Pb in the south section is higher than that of the north section, and in the shear zone it is close to that of sea salt. Anthropogenic Pb by calculation is larger than 99%. Its main sources are polluted air masses origi nation from Europe and the midpart of Russia, as well as the western North America and far east Russia. This is also conformed by 206Pb/ 207Pb.  相似文献   

20.
用球形光学模型和核反应多步过程的半经典理论,计算了入射能量在1.0keV-20MeV的中子与^204Pb,^206Pb,^207Pb,^206Pb,和^NatPb相互作用的全套核反应数据,计算结果与评价实验数据比较,符合较好。  相似文献   

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