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11.
Uptodate,rapidpurificationofmixedproteininlargescalehasbeenanimportantresearchprojectinbioengineeringproductprocessing.Immobilizedmetalionaffinitychromatography(IMAC)isanefficientmethodextensivelyusedforaffinitypurificationofbiologicallyactivesubstance…  相似文献   
12.
钨辐射损伤随辐照剂量变化的重离子辐照模拟研究   总被引:1,自引:0,他引:1  
采用重离子辐照模拟方法和正电子湮没寿命测量技术研究了钨辐射损伤随辐照剂量的变化。20,60和90dpa(每个原子的位移次数)辐照损伤水平的实验结果表明,辐照在钨中产生单空位、双空位、位错和空位团等缺陷;随辐照剂量的增大,单空位、双空位和位错浓度增加,空位团的尺度和浓度都随之增大。Radiation damage in W has been studied as a function of irradiation dose by heavy ion simulation and positron annihilation lifetime measurement. The experimental results of 20, 60 and 90 dpa irradiations illustrate that the mono-and di-vacancies, dislocations and vacancy clusters are produced by the irradiation. The concentrations of the mono-and di-vacancies and dislocations and both the concentration and size of the vacancy clusters or voids all increase with the increasing of the irradiation dose.  相似文献   
13.
在77—295 K温区和氢浓度0—0.35范围采用正电子湮没寿命测量方法研究了Pd0.75Ag0.25Hx氢化物合金. 充氢后正电子湮没寿命谱可以用两个寿命成分表征. 短寿命成分τ1不随温度和氢浓度变化, 是自由正电子湮没寿命; 长寿命成分τ2及其相对强度I2不随温度变化, 但随氢浓度的增加分别增大和减小, τ2是氢气泡捕获的正电子湮没寿命, τ2增大和I2减小说明随氢浓度增大氢聚集成的气泡的尺度增大, 而浓度减小. 实验结果表明, 氢脆的微观机理是氢气泡致脆. The metal hydride PdAgHx with a hydrogen concentration x ranging from 0 to 0.35 has been investigated by positron annihilation lifetime method in the temperature region between 77 K and 295 K. The measured lifetime spectra in metal hydride PdAgHx are characterized by two lifetimes τ1 and τ2. The short lifetime τ1 is independent of both hydrogen concentration and temperature, which is ascribed to the annihilation lifetime of free positrons. The long lifetime τ2 and its intensity I2 do not change with temperature, while τ2 increases and I2 decreases with increasing of hydrogen concentration. τ2 is attributed to the lifetime of positrons trapped at the hydrogen bubble. The increase of τ2 indicates the growth of the hydrogen bubble, and the decrease of I2 shows the reduction of the hydrogen bubble concentration. The experimental result shows a microscopic mechanism that the hydrogen bubble produced causes hydrogen embrittlement.  相似文献   
14.
5.28×1016cm-2 85MeV 19 F辐照的α-Al2O3中,在其热退火过程中采用正电子湮没方法首次观察到了空洞. 450℃退火开始产生空洞,550℃到750℃空洞半径约为0.29nm不随温度变化,但浓度随温度增加而增加;高于750℃,空洞半径随温度升高迅速增大,1050℃时空洞的半径达1.10nm.  相似文献   
15.
介绍了在中国原子能科学研究院建成的我国第一台βNMR及βNQR谱仪.进行了12B的寿命、磁矩和极化度的测量,实验结果表明谱仪工作可靠  相似文献   
16.
乳状液膜体系分离提取铜离子   总被引:1,自引:0,他引:1  
以Span80-对氨基苯磺酸(APS)-NH3液膜体系分离提取Cu2+。最佳分离条件为:制乳搅拌速度3500r/min,制乳时间及乳水混合时间分别为10min和20min,乳水比和油内比分别为0.38和0.44,APS、Span80和液体石蜡浓度分别为11%、4.4%和2.2%,内相NH3和外相HCl浓度分别为4.0mol/L和0.5mol/L。用该体系分离提取了模拟样中的Cu2+。  相似文献   
17.
The g-factors of the positive parity rotational levels up to spin Ⅰ= 41/2 in ^83Y have been measured by a transient-magnetic-field ion implantation perturbed angular distribution method. The experimentally measured g-factors show the g9/2 proton alignment followed by the g9/2 neutron alignment. The measured g-factors are in good agreement with the results calculated by an empirical formula based on the cranking shell model.  相似文献   
18.
用时间微分扰动角关联方法测量了LaFeO3纳米中的电四极超精细相互作用. 扰动角关联探针核14057La 14058Ce由139La(n,γ)140La反应产生, 实验只观察到一个La晶位的四极相互作用. 在室温下, 20和40 nm 以及晶体LaFeO3的四极相互作用频率ω0分别为 687.4 , 698.3 和742.9 Mrad/s , 频率分布宽度系数σ分别为 0.014, 0.009和0.001, 电场梯度不对称系数η=0. 实验数据表明, 电场梯度主轴与晶轴方向一致; 样品具有菱方结构, 晶体到纳米发生菱方向正交结构转变, 纳米尺度越小, 越趋于正交结构; 由于邻近核的扰动, 随纳米颗粒增大, 四极相互作用频率分布宽度系数σ变小, 晶体时最小. The quadrupole interactions in the nano and crystalline LaFeO3 perovskites have been investigated by TDPAC. The TDPAC probing nuclei 14057La 14058Ce were produced through the nuclear reaction 139La(n.γ)140La at the CIAE heavy water experimental reactor. One electric quadrupole interaction was detected for each material, which is assigned to the La site. The quadrupole interaction frequencies of 687.4, 698.3 and 742.9 Mrad/s with a distribution coefficient of 0.014, 0.009 and 0.001 were observed at room temperature for the 20 and 40 nm nano LaFeO3 and crystalline LaFeO3, respectively. The fitting yielded the EFG asymmetry parameter η=0, which indicates that the principal axes of the EFG is aligned with the crystallographic axes. The experimental results show that the structure of crystalline LaFeO3 is rhombohedral, the changing of the structure towards the orthorhombic structure takes place from the crystalline LaFeO3 to the nano LaFeO3, and the smaller the nano grain size, the larger the change. The frequency distribution is caused by the perturbation of the neighboring atoms, and thus, the distribution coefficient increases with decreasing the nano grain size and the crystalline LaFeO3 arrives at its maximum.  相似文献   
19.
以尼龙66膜为基质,用环氧氯丙烷、戊二醛、二溴丙烷、羰基二咪唑试剂对用盐酸水解后的尼龙66膜进行活化,共价键合上乙二胺、己二胺等不同长度的间隔臂和组氨酸、粘多菌素B等亲和配基,配基含量达30μmol/g以上。亲和膜装入专门设计制造的膜分离器中,能有效地去除水溶液中的内毒素,去除率一般在90%以上。该膜对内毒素的亲和容量为02mg/g,表观脱附常数为304×10-8mol/L,亲和膜可用碱、脱氧胆酸钠、盐、无热原水进行洗涤再生。  相似文献   
20.
The quadrupole interaction in nano-soft magnetic material Fe73.5Cu1Nb3Si13.5B9 has been studied by perturbed angular correlation using 62Zn probe nuclei from the ISOL radioactive nuclear beam facility at CIAE HI-13 tandem accelerator. Two quadrupole interaction frequencies ω01=440 Mrad/s with a distribution width σ=0 and ω02=90 Mrad/s with a width σ=0.48 are obtained. The fractions of ω01 and ω02 are 38% and 62%, respectively. The measured quadruple interaction parameters indicate that 62% of the implanted 62Zn are located in the grain boundary and 32% in the grain.  相似文献   
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