首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
铜锌超氧化物歧化酶与色氨酸钴(Ⅱ)的相互作用   总被引:1,自引:1,他引:0  
采用VIS、ICP及酶活性测定等方法,研究铜锌超氧歧化酶(Cu2Zn2SOD)与色氨酸钴(Ⅱ)(Co(Trp)^n)的直接相互作用以及外加色氨酸钴(Ⅱ)的量、溶液pH值对此类相互作用的影响。结果发现:在水溶液中原酶活性中心处的Zn(Ⅱ)离子可被外加的色氨酸钴(Ⅱ)部分诱导、交换出来,而溶液中外加的Co(Trp)^n中的Co(Ⅱ进入酶的活性中心,形成“Co-SOD”酶衍生物,并相应影响了酶的催化活性  相似文献   

2.
采用VIS和ICP及酶活性测定等方法,研究铜锌超氧歧化酶(Cu2ZnSOD)与组氨酸钴(Ⅱ)〖Co(His)〗的直接相互作用及外加组氨酸钴(Ⅱ)、磷酸盐对此类相互作用的影响。结果发现,水溶液中原酶活性中心Cu(Ⅱ)和Zn(Ⅱ)离子可被外加的组氨酸钴(Ⅱ)部分诱导,交换出来,而Co(His)。中的Co(Ⅱ)进入酶的活性中心,形成“Co-SOD”酶衍生物各组分,并相应影响了酶的催化活性。与此同时,外加  相似文献   

3.
采用VIS和 ICP及酶活性测定等方法,研究铜锌超氧歧化酶(Cu2Zn2SOD)与组氨酸钴(Ⅱ)[Co(His)n] 的直接相互作用及外加组氨酸钴(Ⅱ)、磷酸盐对此类相互作用的影响。结果发现,水溶液中原酶活性中心的Cu(Ⅱ)和Zn(Ⅱ)离子可被外加的组氨酸钴(Ⅱ)部分诱导、交换出来,而Co(His)n 中的Co(Ⅱ)进入酶的活性中心,形成“Co-SOD”酶衍生物各组分,并相应影响了酶的催化活性。与此同时,外加组氨酸钴(Ⅱ)及磷酸盐对此类相互作用有着重要的影响  相似文献   

4.
Co2+-L-赖氨酸的合成及其X射线光谱研究   总被引:2,自引:2,他引:0  
本文以氯化钴和L-赖氨酸为原料,合成了Cl^2+-L=赖氨酸配合物,对配合物进行了钴含量的测定,并且观测了配合物的X射线光谱,确定了钴离子与L-赖氨酸的配位形式。  相似文献   

5.
Co(DC)2-NaDC凝胶复合络合物的研究   总被引:2,自引:0,他引:2  
本文利用红外光谱(FTIR)、X-射线粉末衍射谱,并配合ICP分析,对在水溶液中不同浓度和反应配比的NaDC脱氧胆酸钠和CoCl2反应生成的一系列脱氧胆酸金属络保物的组成和结构进行了研究。当NaDC的反应浓度在C.M.C以上,且Co^2+离子浓度较高时,或当NaDC的反应浓度在C.M.C以下时,Co^2+离子与单分子NaDC作用,生成结晶度很好的絮状Co(DC)2脱氧胆酸钴沉淀,其组成为Co(DC  相似文献   

6.
用紫外光谱研究了等离子点时1:1Co(Ⅱ)-HSA配合物金属中心的结构,结果表明:该配合物的中心钴在低浓度时以Co(Ⅱ)和Co(Ⅲ)两种氧化态共存,高浓度时(>3.0×10-4mol·L-1)仅以Co(Ⅲ)氧化态存在;且金属中心随着浓度增大发生"八面体→四方锥→四方平面"的构型变化。与生理pH时金属中心的结构存在显著差别,可用pH效应加以解释。  相似文献   

7.
合成了新试剂二安替比林-(邻-乙氧基)苯基甲烷(DAoEM),根据Cu^2+对H3PO4-Mn(Ⅱ)-Cr(Ⅵ)-DAoEM显色体系的干扰褪色作用,建立了一个测定微量铜的新方法,其检出限为4×10^-6g/L,铜离子含量在20-160μg/L范围内与1g(A0/A)成良好线性关系,体系稳定性和选择性良好,用于铅样中痕量铜的测定,结果满意。  相似文献   

8.
火焰原子吸收法测定海水中的铜和钴   总被引:11,自引:3,他引:8  
王森勋  王锋  马峰 《光谱实验室》2000,17(2):207-209
本文用火焰原子吸收光谱法测定海水中的铜,钴,方法简单,快捷,具有良好的精密度和准确性。本法的相对标准偏差为Cu3.9%-5.0%,Co1.6%-3.1%,回收率为Cu93% ̄103.5%,Co94.4% ̄105%。  相似文献   

9.
硫氰酸铵树脂相分光光度法同时测定天然水中微量铁和钴   总被引:4,自引:0,他引:4  
研究了在Tween-80存在的酸性介质中,Fe(Ⅲ)和Co(Ⅱ)与SCN^-形成稳定的有色络阴离子与阴树脂交换吸附,有色络合物富集显色于树脂组上,进行树脂组分光光度集显色于树脂相上,进行树脂相分光光度法同时测定铁和钴的实验条件,Fe(Ⅲ)和Co(Ⅱ)树脂具有色络合物最大吸收波长λmax分别为490nm和630nm,摩尔吸光系数,ε为2.4×10^5L.mol^-1.cm^-1和2.1×10^5L.  相似文献   

10.
采用等量分步浸渍法先后将Co与贵金属组份浸于CeO2上,经500℃焙烧2h,450℃氢气还原1h制得Co-Pt/CeO2和Co-Rh/CeO2催化剂。活性测试结果表明,贵金属与Co之间具有催化协同效应。对CO氧化,Pt与Co的协同效应较显著,而对富氧条件下CH4选择还原NO,Rh与Co的协同效应更为明显,XPS和EXAFS结果一致表明,经H2还原后,样品Co/CeO2、Co-Pt/CeO2和Co-  相似文献   

11.
Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.  相似文献   

12.
A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.  相似文献   

13.
A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.  相似文献   

14.
Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·104 Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.  相似文献   

15.
A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.  相似文献   

16.
Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.  相似文献   

17.
18.
The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.  相似文献   

19.
The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号