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1.
四苯基卟啉及其系列衍生物电子光谱的IDNO/CI研究   总被引:2,自引:0,他引:2  
运用MNDO计算和群论,优化得到了较满意的中位取代四苯基卟啉的分子构型,并结合INDO/CI方法,对四苯基卟啉及其系列衍生物进行了电子结构的研究和电子光谱主要吸收带的指认。对卟啉系列衍生物的取代基效应进行了讨论,得到一些有益的结论。  相似文献   

2.
用化学方法合成了四苯基卟啉(TPP)、四苯基卟啉乙酸合锰(TPPMn)、四对羟基苯基卟啉(THPP),并用太赫兹时域光谱技术研究了室温条件下这三种化合物的光谱特征,得到了各自的时域谱和透射谱。结果表明不同的卟啉化合物在太赫兹波段有不同的吸收,四苯基卟啉与四苯基卟啉乙酸合锰透射峰的位置相同,可能由于金属原予在大分子环内部配位,对分子的振动模式无影响,只是增强了物质对THz的吸收。通过比较样品的透射谱,讨论了卟啉分子结构与THz光谱吸收的关系。  相似文献   

3.
运用MNDO计算和群论,优化得到了较满意的中位取代四苯基卟啉(H2TPP)的分子构型。并结合INDO/CI方法,对四苯基卟啉及其系列衍生物进行了电子结构的研究和电子光谱主要吸收带的指认。提出五分子轨道模型,揭示了卟啉类化合物电子光谱典型特征的内在原因,计算结果能与实验值较好符合。对卟啉系列衍生物的取代基效应进行了讨论,得到一些有益的结论。  相似文献   

4.
讨论了金属离子Mn(Ⅲ),Fe(Ⅲ),Rh(Ⅲ)和Pd(Ⅱ)原卟啉Ⅸ-二甲酯(PP)和四苯基卟啉(TPP)配合物及Pd(Ⅱ)间氯四苯基卟啉(TPPm-cl)配合物的共振拉曼光谱。利用金属离子外层d电子与卟啉环的作用,解释了配合物结构灵敏带的变化规律,同时讨论了不同卟啉及卟啉环上取代基团对结构灵敏带的影响。  相似文献   

5.
两种新型对称卟啉的合成及紫外可见光谱特性研究   总被引:5,自引:0,他引:5  
本文采用一种新型的合成方法合成了两种新型对称卟啉meso-四(对苯甲酰胺基苯基)卟啉和meso-四(邻苯甲酰胺基苯基)卟啉,用元素分析,红外光谱,核磁共振谱对两种卟啉进行了表征,并对其紫外可见光谱特性进行了研究。  相似文献   

6.
研究了5(4-缬氨酸丁氧苯基)-10,15,20-三(4-氯苯基)卟啉锌与嘧啶在氯仿溶液中轴配反应光谱和热力学性质。用紫外-可见分光光度法测定了轴向配位反应体系的配位数和平衡常数。用温度系数法求得了轴配反应的标准摩尔焓变和标准摩尔熵变。探讨了温度对轴向配位反应的影响。  相似文献   

7.
β-甲酰基四苯基卟啉的一锅法合成与光谱表征   总被引:1,自引:0,他引:1  
以四苯基卟啉为原料,"一锅法"和超声结合制备β-甲酰基四苯基卟啉。目标产物产率约61%。产物经紫外-可见光谱、红外光谱、氢核磁共振谱进行结构表征。  相似文献   

8.
合成了四(对甲氧基苯基)钴卟啉,利用荧光光谱法研究了四(对甲氧基苯基)钴卟啉与牛血清白蛋白的相互作用,由实验数据计算求得该卟啉与牛血清白蛋白的双分子猝灭过程速率常数Kq=9.619×1012L·mol-1.s-1、结合常数KA=3.475×103L·mol-1、结合数n=0.6893,结果表明:四(对甲氧基苯基)钴卟啉与牛血清白蛋白之间发生了较强的静态荧光猝灭作用。  相似文献   

9.
中位-四l-(对十六酰氧基)苯基卟啉的合成与表征   总被引:7,自引:2,他引:5  
本文以四-(对羟基苯基)卟啉与十六酰氯为原料,通过酯化反应合成了中位-四-(对十六酰氧基苯基)卟啉,采用红外光谱监测了反应进程,以硅胶为固定相,氯仿为洗脱剂采用柱层析方法对反应产物进行了分离与提纯。最后用元素分析,紫外可见光谱,红外光声光谱,核磁共振氢谱,摩尔电导等手段对合成产物进行了结构表征,对主要的紫外光谱,红外光谱及核磁共振氢谱吸收带进行了经验归属,初步确定了合成产物的结构。  相似文献   

10.
2,5—二(甲基苯基)—1,3,4—恶二唑的红外光谱特性   总被引:1,自引:0,他引:1  
本文用红外光谱法研究了2,5-(邻甲基苯基)-1,3,4-恶二唑和2,5-二(间甲基苯基)-1,3,4-恶二唑的红外光谱特性,并对其主要谱带进行了指认和比较。  相似文献   

11.
12.
Gas-phase emission spectra of the hitherto unknown free radical TeLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which tellurium vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Two systems of blue-degraded bands were measured at high spectral resolution in the ranges 8000-9000 and 5700-6700 cm(-1) and vibrational and rotational analyses were performed. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of TeLi and the isovalent TeH and also electric dipole transition moments connecting them. As in the TeH system, the ground state of TeLi is found to be X(2)Pi(i), but with a remarkably smaller spin-orbit splitting. The TeLi calculations indicate a strongly bound A(2)Sigma(+) state, while in TeH the analogous state is computed to lie significantly higher at approximately 32 000 cm(-1), and it is strongly predissociated. Based on the theoretical analysis, the observed TeLi band systems are assigned to the transitions A(2)Sigma(+)(A1/2)-->X(1)(2)Pi(3/2)(X(1)3/2) and A(2)Sigma(+)(A1/2)-->X(2)(2)Pi(1/2)(X(2)1/2). Analysis of the spectra has yielded the molecular constants (in cm(-1)) X(1)(2)Pi(3/2):omega(e)=457.49(3), omega(e)x(e)=2.482(9), B(0)=0.408908(8); X(2)(2)Pi(1/2): T(e)=2353.44(3), omega(e)=456.28(4), omega(e)x(e)=2.635(8), B(0)=0.414954(8), p(0)=1.00637(4); A(2)Sigma(+): T(e)=8574.64(2), omega(e)=437.81(3), omega(e)x(e)=2.581(8), B(0)=0.423903(8), p(0)=-0.19915(2), where the numbers in parentheses are the standard deviations of the parameters. Comparison of the isovalent TeLi and TeH systems emphasizes that the difference in bonding character (ionic in TeLi vs covalent in TeH) is responsible for qualitative differences in the electronic spectra of these two molecules. Copyright 2001 Academic Press.  相似文献   

13.
Possible mechanisms of plastic deformation and failure of nanostructured and cluster amorphous materials have been considered. It is shown that the most probable carriers of plastic deformation in these materials are macrodislocations—linear topological defects of the regular nanocrystallite packing in the nanostructure or cluster packing in amorphous materials. Continuum models are proposed to describe the processes of plastic deformation and failure of nanostructured and cluster amorphous materials. Original Russian Text ? L.S. Vasil’ev, S.F. Lomaeva, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 1, pp. 128–131.  相似文献   

14.
NO formation and flame propagation are studied in premixed flames of iso- and n-isomers of butane and butanol through experimental measurements and direct simulation of experimental profiles. The stabilized flame is realized through the impingement of a premixed combustible jet from a contraction nozzle against a temperature-controlled plate. The velocity field is obtained by means of Particle Image Velocimetry (PIV) and nitric oxide concentration profiles are measured using Planar Laser Induced Fluorescence (PLIF), calibrated using known NO seeding levels. It is found that NO formation in n- and iso-isomers is comparable under the conditions considered, except for rich butanol mixtures, whereby NO formation is higher for iso-butanol. Generally, less NO is formed in butanol flames than in the butane flames. The experiment is simulated by a 1D chemically reacting stagnation flow model, using literature models of C1–C4 hydrocarbons [Wang et al., 2010] and butanol combustion chemistry [Sarathy et al., 2009, 2012]. NO prediction is tested using two of these mechanisms with a previously-published NOx submechanism added into the butane and butanol models. While a good level of agreement is observed in the velocity field prediction under lean and stoichiometric conditions, discrepancies exist under rich conditions. Greater discrepancies are observed in NO prediction, except for the C1–C4 mechanism which shows good agreement with the experiment under lean and stoichiometric conditions. The current study provides data for further development of mechanisms with NOx prediction capabilities for the fuels considered here.  相似文献   

15.
An original technology and the properties of new thin film nanoobjects, free films and shells of molecular and atomic thicknesses, are presented. Special attention is paid to shells of monoatomic or monomoleculer thickness with unique surface properties that have not been found in bulk materials.  相似文献   

16.
We solve several problems that involve imposing metrics on surfaces. The problem of a strip with a linear metric gradient is formulated in terms of a Lagrangian similar to those used for spin systems. We are able to show that the low energy state of long strips is a twisted helical state like a telephone cord. We then extend the techniques used in this solution to two–dimensional sheets with more general metrics. We find evolution equations and show that when they are not singular, a surface is determined by knowledge of its metric, and the shape of the surface along one line. Finally, we provide numerical evidence by minimizing a suitable energy functional that once these evolution equations become singular, either the surface is not differentiable, or else the metric deviates from the target metric.  相似文献   

17.
Hollow spheres and nanospheres of Au have been prepared by a simple reaction of HAuCl4·4H2O, NaOH and (NH2OH)2·H2SO4 in the presence of gelatin. The role of gelatin and the effect of the temperature of the reaction in producing the spherical particles of Au are discussed. The products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy and UV–Vis absorption spectroscopy. The sizes of the nanospheres of Au were estimated by the Debye–Scherrer formula according to the XRD spectrum. PACS  81.05.Bx; 81.05.Rm; 81.07.-b; 81.16.Be; 81.20.Fw  相似文献   

18.
Our purpose is to evaluate bias and repeatability of the quantitative MRI sequences QRAPMASTER, based on steady-state imaging, and variable Flip Angle MRF (MRF-VFA), based on the transient response.Both techniques are assessed with a standardized phantom and five volunteers on 1.5 T and 3 T clinical scanners. All scans were repeated eight times in consecutive weeks.In the phantom, the mean bias±95% confidence interval for T1 values with QRAPMASTER was 10 ± 10% on 1.5 T and 4 ± 13% on 3.0 T. The mean bias for T1 values with MRF-vFA was 21 ± 17% on 1.5 T and 9 ± 9% on 3.0 T. For T2 values the mean bias with QRAPMASTER was 12 ± 3% on 1.5 T and 23 ± 1% on 3.0 T. For T2 values the mean bias with MRF-vFA was 17 ± 1% on 1.5 T and 19 ± 2% on 3.0 T. QRAPMASTER estimated lower T1 and T2 values than MRF-vFA. Repeatability was good with low coefficients of variation (CoV). Mean CoV ± 95% confidence interval for T1 were 3.2 ± 0.4% on 1.5 T and 4.5 ± 0.8% on 3.0 T with QRAPMASTER and 2.7% ± 0.2% on 1.5 T and 2.5 ± 0.2% on 3.0 T with MRF-vFA. For T2 were 3.3 ± 1.9% on 1.5 T and 3.2 ± 0.6% on 3.0 T with QRAPMASTER and 2.0 ± 0.4% on 1.5 T and 5.7 ± 1.0% on 3.0 T with MRF-vFA.The in-vivo T1 and T2 are in the range of values previously reported by other authors.The in-vivo mean CoV ± 95% confidence interval in gray matter were for T1 1.7 ± 0.2% using QRAPMASTER and 0.7 ± 0.5% using MRF-vFA and for T2 were 0.9 ± 0.4% using QRAPMASTER and 2.4 ± 0.5% using MRF-vFA. In white matter were for T1 0.9 ± 0.3% using QRAPMASTER and 1.3 ± 1.1% using MRF-vFA and for T2 were 0.7 ± 0.4% using QRAPMASTER and 2.4 ± 0.4% using MRF-vFA. A GLM analysis showed that the variations in T1 and T2 mainly depend on the field strength and the subject, but not on the follow-up repetition in different days. This confirms the high repeatability of QRAPMASTER and MRF-vFA.In summary, QRAPMASTER and MRF-vFA on both systems were highly repeatable with moderate accuracy, providing results comparable to standard references. While repeatability was similar for both methods, QRAPMASTER was more accurate. QRAPMASTER is a tested commercial product but MRF-vFA is 4.77 times faster, which would ease the inclusion of quantitative relaxometry.  相似文献   

19.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 3, pp. 396–402, September, 1990.  相似文献   

20.
受控核聚变两大途径的对比与结合   总被引:6,自引:0,他引:6  
谭宝林 《物理》2002,31(3):159-161
目前人们探索受控核聚变主要是从两个方向着手:磁约束受控核聚变和惯性约束受控核聚变,但目前还无法判定到底哪一种途径更为可取,文章首先对这两种途径进行对比,指出各自的特点和困难,在此基础上提出了一种结构相对简单,成本相对较低的三轴六极磁镜系统设想,希望能将磁约束和惯性约束和惯性约束结合起来,以实现受控核聚变反应。  相似文献   

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