452 resultados para infrared spectrometry
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本学位论文分为四个部分,第一部分报道了用串联质谱快速分析合成药物中的微量杂质成分以及分析中药材中的化学成分。第二部分报道了通过质谱和串联质谱发现并合成新型的PdPincer 催化剂,同时对其活性进行测试。第三部分为串联质谱自动解析软件的设计及应用。第四部分概述了应用在质谱中的各种碎裂方式。 第一部分首先总结了5-溴粉防己碱及其类似物的裂解规律,并以此为根据推测出2 个微量杂质的结构。随后针对无患子(Sapindus mukurossi Gatren.)中的皂苷成分,由ESI-QTOF 得到各个皂苷成份的高分辨质量数据进而得到其分子式,然后利用ESI-IT 电喷雾串联质谱对无患子总皂苷中各皂苷成分的结构进行进一步的鉴定。进而以同样的方式,先通过ESI-QTOF 得到黄山药(Dioscoreapanthaica)总皂苷中各个组分化合物的分子式,然后对已有的薯蓣皂苷标准品做串联质谱分析,以得到该类化合物的裂解规律并给出解析该类化合物的流程图。在此利用计算化学的方法讨论了离子的丰度与裂解活化能之间的关系。然后应用APCI-MS/MS 方法探讨了四对同分异构体和几个已知的化合物,并最后用液质联用对其进行确认,同时还给出了4 个未知化合物的可能结构。 第二部分报道通过质谱和串联质谱发现并合成新型的PdPincer 催化剂,同时对其活性进行测试。钯催化的交联反应是有机合成中C-C 键形成的最有效的方法,且硫脲是一类对空气和水都稳定的化合物,因此我们设计并合成了一系列的硫脲钯催化剂并得到了很好的催化活性。我们在对其中一类环状双硫脲化合物进行质谱实验的时候,在正离子模式下发现了反常的[M.H]+,通过串联质谱进一步确定了它是一种新型的PdPincer 结构。我们将其合成出来并通过X-ray 衍射实验确定了它的结构。同时测定其催化活性并与未形成pincer 的类似物进行比较发现该类化合物具有较宽的底物适用性。 第三部分为串联质谱自动解析软件的设计及应用。通过前面两部分的启示,独立设计开发了AuMass(1.0)。其算法是:先通过查找特殊的碎片离子,中性丢失或碎片离子质量差来确定某类化合物的骨架结构,然后利用该类化合物的自动解析流程来对其周边取代基进行确认。通过它快速地对白芍中的化学成分进行解析,并对未知的化合物进行了推测。为了增加它的解析能力,我又对其它类型的化合物裂解规律进行总结,并给出了自动解析流程。实践证明该软件具有相当好的应用价值。 第四部分综述了应用在质谱上的各类母离子的碎裂技术。这里包括了碰撞诱导裂解(CID)、光诱导碎裂(LID)、电子捕获裂解/电子转移裂解(ECD/ETD)、红外多光子解离(IRMPD)、黑体辐射解离(BIRD)和PQD 裂解技术。 This dissertation consists of four chapters. The first chapter reports the rapidanalysis of trace impurities from synthetical medicine and analysis of the chemicalconstitutents from Chinese herb medicines. The second chapter elaborates the studieson the discorvery and synthesis of new type of Pd Pincer catalyst by using MS andtandem MS together with the testing of its catalyst activity. The third chapter dwellson the designation and development of automatic tandem mass spectrometry analysissoftware. The last chapter presents a review on the dissociation technique of massspectrometry. The first chapter reports the rapid analysis of trace impurities from synthesismedicine and analysis of the chemical constitutents from Chinese herb medicines. The fission mechanism of 5-bromotetrandrine was obtained by analysis of the dissociationpathways of major product, by using which the possible structure of the two traceimpurties was assumed. There are lots of saponins in Sapindus mukurossi. Except forthe good spumescence and decontamination,it possesses the bioactivity of antigenand antitch. First of all, the high resolution mass information was obtained by ESI-QTOF. Hence the possible molecular formulars were acquired too. Then weconducted the further detection of the structures of its saponins by using ESI-ITtechnology. In the same manner, first the molecular formulars of every constituentfrom Dioscorea panthaica in total saponins were obtained by ESI-QTOF, and thenacquired the fission mechanism of this type of compounds by tandem massexperiment on a series of known and available saponins. In the same time, theanalysis flowchart was concluded. Here the relationship between the ion intensity andthe corresponding dissiociation activation energy was studied by computer chemistry.Then the four pairs of isomers were differentiated by APCI-MS/MS, as well as thecharacterization of known and unknown compounds. The assumption was confirmed by HPLC-MS/MS. Among them the possible structures of four unknown saponinswas presented. The second part was discovery and synthesis of a new type of Pd pincer catalystby MS and tandem MS. The coupling reaction catalyzed by Pd is the most effectivemethod in C-C formation in organic synthesis. Apart from that, thiourea is type ofcompounds that are stable to atmosphere and moisture. Hence we designed a series ofPd thiourea catalysts. Some of them show the excellent catalyst activity. The abnormalparent ion [M.H]+ was founded in positive ESI mode when we conduct some massspectrometry experiments on the bicyclical thiourea Pd complex. The structure wasproposed by mass and tandem mass spectrometry. Because it was a new type of pincer,we want to test its catalyst activity. So the Pd pincer was synthesized and the detailstructure was obtained by x-ray experiment. It shows the more fitness in catalysis ofSuzuki reaction by comparison with the analogue. The third chapter dwells on the design and development of automatic tandemmass spectrometry analysis software. Inspired by the former two chapters, theAuMass (version 1.0) was developed. Its algorithm is: first check the diagnostic ion,diagnostic neutral loss or diagnostic ions mass intervals in database to find out whatthe analyst’s skeleton belongs to, then identify the peripheral functional group by thecorresponding analysis flowchart. The chemical constituents of Paeonia lactiflorawere identified rapidly by using AuMass. To increase the analysis ability, the othertypes of compounds from Chinese herbs was concluded. Actually, the software isproven to have the much valuable application. The last chapter presented the review on the some kinds of fission technique ofmass spectrometry. It involves the collision induced dissociation (CID), laser induceddissociation (LID), electron capture dissociation/electron transfer dissociation(ECD/ETD), infrared multiple photons dissiociation, black body irraditiondissociation and PQD fission technique from Finnigan.
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Preparation of 238U on 2μm Al foils by molecular plating technique is described. In order to obtain optimum conditions for deposition, several parameters influencing the quality of layers such as current density, distance between the anode and cathode and the deposition time were investigated. The target thickness was determined by spectrophotometry. The uniformity and morphology of the target surface were studied by means of scanning electron microscopy, energy dispersive X-ray spectrometry and Infrared spectra. The results show that uranium is deposited in its oxide or hydroxide form uniformly and adherently onto the foil.
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The highly charged ion Ar-40(16+) with the velocity (kinetic energy E (K)=150 keV, velocity V=8.5x10(5) m/s) smaller than Bohr velocity (V (Bohr)=2.9x10(6) m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier model.
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Single-crystalline spinel (MgAl2O4) specimens were implanted with helium ions of 100 keV at three successively increasing fluences of (0.5, 2.0 and 8.0) x 10(16) ions/cm(2) at room temperature. The specimens were subsequently annealed in vacuum at different temperatures ranging from 500 to 1100 degrees C. Different techniques, including Fourier transformed infrared spectroscopy (FTIR), thermal desorption spectrometry (TDS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the specimens, It was found that the absorbance peak in the FTIR due to the stretching vibration of the Al-O bond shifts to smaller wave numbers with increasing fluence, shifting back to larger wave numbers with an increase of annealing temperature. The absorbance peak shift has a linear relationship with the fluence increase in the as-implanted state, while it does not have a linear relationship with the fluence increase after the annealing process. Surface deformation occurred in the specimens implanted with fluences of 2.0 and 8.0 x 10(16) ions/cm(2) in the annealing process. The phenomena described above can be attributed to differences in defect formation in the specimens. (C) 2008 Elsevier B.V. All rights reserved.
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Defect engineering for SiO2] precipitation is investigated using He-ion implantation as the first stage of separation by implanted oxygen (STMOX). Cavities are created in Si by implantation with helium ions. After thermal annealing at different temperatures, the sample is implanted with 120keV 8.0 x 10(16) cm(-2) O ions. The O ion energy is chosen such that the peak of the concentration distribution is centred at the cavity band. For comparison, another sample is implanted with O ions alone. Cross-sectional transmission electron microscopy (XTEM), Fourier transform infrared absorbance spectrometry (FTIR) and atomic force microscopy (AFM) measurements are used to investigate the samples. The results show that a narrow nano-cavity layer is found to be excellent nucleation sites that effectively assisted SiO2 formation and released crystal lattice strain associated with silicon oxidation.
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用速度不同的(动能EK=272和357keV,速度v=1.14×106和1.72×106m/s)的高电荷态离子40Ar17+分别入射金属Be表面,同时测量这种相互作用过程中产生的近红外光谱线和X射线谱。实验结果表明,在低速范围内(速度小于玻尔速度vBohr=2.19×106m/s),速度较小的40Ar17+离子在到达金属的表面临界距离Rc到进入表面(2—3原子层)的进程中,形成了较多的高激发态Ar原子,其退激辐射较强的光谱线,进而验证了经典过垒模型。
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Single crystals of 6H-SiC were implanted at 600 K with 100 key He ions to three successively fluences and subsequently annealed at different temperatures ranging from 873 to 1473 K in vacuum. The recovery of lattice damage was investigated by different techniques including Rutherford backscattering spectrometry in channeling geometry, Raman spectroscopy and Fourier transform infrared spectroscopy. All three techniques showed that the damage induced by helium ion implantation in the lattice is closely related to the fluence. Rutherford backscattering spectrometry/channeling data on high temperature implantations suggest that for a fluence of 3 x 10(16) He+/cm(2), extended defects are created by thermal annealing to 1473 K. Apart from a well-known intensity decrease of scattering peaks in Raman spectroscopy it was found that the absorbance peak in Fourier transform infrared spectroscopy due to the stretching vibration of Si-C bond shifted to smaller wave numbers with increasing fluence, shifting back to larger wave numbers with increasing annealing temperature. These phenomena are attributed to different lattice damage behavior induced by the hot implantation process, in which simultaneous recovery was prevailing. (C) 2010 Elsevier B.V. All rights reserved.