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991.
目的:对1名生育过眼皮肤白化病(OCA)先证者母亲再次怀孕的家庭进行酪氨酸酶(TYR)基因突变研究和产前基因诊断.方法:应用聚合酶链反应(PCR)技术扩增TYR基因各外显子、外显子内含子交界区及启动子区,分别以异源双链分析法(HA)、变性高效液相层析(DHPLC)和DNA序列测定技术分析先证者及其父母的基因突变,明确突变的致病性后,检测胎儿TYR基因相应位点与基因型.结果:先证者的基因型为c.232_233insGGG/c.841G>T,其父母基因型分别为c.232_233insGGG和c.841G >T突变杂合子.E281X具有致病性.胎儿未获得父亲的c.232_233insGGG突变和母亲的c.841G >T突变.HA和DHPLC法所获得结果与测序结果完全一致.结论:确定了先证者基因型,并检测出一种新的致病性突变c.841G >T.胎儿未获得致病性基因突变,具有正常的基因型. 相似文献
992.
The diluted magnetic semiconductor (DMS), which exploits both the spin and the charge of car- riers, is one of the most important materials to re- alize semiconductor spintronies.Many research works have been focused on the magnetic properties of Mn-doped ZnO due to its room-temperature ferro- magnetism (RT-FM), which is very important for commercial applications. Recently, Mn-doped ZnO nanostruetures were developed for the nano spintronic devices, and kinds of Mn-doped ZnO nanostrue- tures have been prepared with room-temperature fer- romagnetic behavior, while conflicting arguments produced no consensus on the origin of RT-FM in these systems. Vinod et al. reported that the RT-FM in 5 wt% Mn-doped ZnO nanorods is attributed to the increase in the specific area of grain boundaries and the interaction between Mn2+ ions and Zn2+ ions.Yihnaz et al. found that bound magnetic polarons are responsible to the RT-FM. Gao et al. reported that the exchange interaction between the donor electron trapped by the singly ionized oxygen vacancy and sur- rounding Mn ions is responsible for the RT-FM. It was also reported that the ferromagnetism of the Mn-doped ZnO nanowires could be controlled by the electric-field or Mn doping levels. This work will investigate the magnetic property of the Mn-doped ZnO nanowires grown by the chemical vapor deposi- tion (CVD) method under the air condition and under the vacuum condition, respectively, and it is found that crystalline quality plays an important role to-wards the room-temperature ferromagnetic behavior of the doped nanowires. 相似文献
993.
新生入学教育一直是我国高校思想政治教育工作的重要组成部分,它不仅担负着引导新生完成从高中生活到大学生活的过渡,更是为他们提供了一个未来几年内所要遵从的理念和框架,然而,当下我们的新生入学教育却存在着诸多问题,如形式单一、效果不理想等,这些都是摆在我们面前的问题.如今,时代在变迁,我们工作面对的都是大学生,可是他们的生活方式和思维模式却大不相同,如果入学教育的内容设置长久不变,很难想象这样的教育活动会收到预想的效果. 相似文献
994.
We investigate the applicability of the independent atom model (IAM) to elastic electron scattering from complex polyatomic molecules, namely C4H10 and C6H6, in the energy range 100-1000eV. The cross sections of the elastic electron scattering are calculated by employing the IAM together with the relativistic partial waves. The incorporation of both the modified absorption potential and the extended structural factor in the IAM makes the elastic differential cross sections and momentum transfer cross sections have a good agreement with the available experimental data. The present simple model seems to be insensitive to the complexity of the target molecules so that the proposed procedure can be quite useful for calculation of electron scattering from bio-molecules. 相似文献
995.
实验采用一个内腔布儒斯特双轴锥棱镜,在掺镱多模双包层光纤激光器中实现了径向偏振光振荡,并在长2 m的增益光纤中获得了高达6.2 mW的功率输出.研究揭示了从光纤激光器振荡中获得径向偏振光的新途径.然而,该激光器输出的径向偏振光的光强分布并不很均匀,且偏振消光比较低,需要进一步改进. 相似文献
996.
997.
对DMBEⅣ势能面进行了特性分析,图示出了其主要地貌特征。利用该势能面进行HO2(总角动量J=0)束缚态的计算,计算结果与该势能面特性相吻合。将计算结果与实验测量值相对照,说明DMBEⅣ势能还有待改进 相似文献
998.
We illustrate typical experimental reaction cross sections cr n which have obtained on RIBLL at Heavy Ion Research Facility of the Institute of Modern Physics (IMP) at Lanzhou. The corresponding nuclear radii are extracted from the measured experimental an using the Glauber model. Meanwhile, theoretical nuclear radii are also calculated using Relativistic density-dependent Hartree and spherical relativistic mean-field theory with Pauli blocking. For comparison, the nuclear radii of these nuclei are a/so calculated using the empirical radius format in which the deformation has been taken into account. From the given experimental and theoretical nuclear radff, we suggest that there may exist proton halo structure in 23A1, 27p and may exist proton skin structure in 24A1. We also find that the deformation plays a great role to the nuclear radii. 相似文献
999.
Stability,electronic structures,and mechanical properties of Fe–Mn–Al system from first-principles calculations 下载免费PDF全文
The stability, electronic structures, and mechanical properties of the Fe–Mn–Al system were determined by firstprinciples calculations. The formation enthalpy and cohesive energy of these Fe–Mn–Al alloys are negative and show that the alloys are thermodynamically stable. Fe_3Al, with the lowest formation enthalpy, is the most stable compound in the Fe–Mn–Al system. The partial density of states, total density of states, and electron density distribution maps of the Fe–Mn–Al alloys were analyzed. The bonding characteristics of these Fe–Mn–Al alloys are mainly combinations of covalent bonding and metallic bonds. The stress-strain method and Voigt–Reuss–Hill approximation were used to calculate the elastic constants and moduli, respectively. Fe_(2.5)Mn_(0.5)Al has the highest bulk modulus, 234.5 GPa. Fe_(1.5)Mn_(1.5)Al has the highest shear modulus and Young's modulus, with values of 98.8 GPa and 259.2 GPa, respectively. These Fe–Mn–Al alloys display disparate anisotropies due to the calculated different shape of the three-dimensional curved surface of the Young's modulus and anisotropic index. Moreover, the anisotropic sound velocities and Debye temperatures of these Fe–Mn–Al alloys were explored. 相似文献
1000.
应用GA-DOSC算法消除果皮影响近红外漫反射光谱分析苹果硬度的研究 总被引:4,自引:0,他引:4
通过偏最小二乘法(PLS)分别建立去皮前后苹果硬度的近红外回归模型.采用光谱附加散射校正(MSC)、微分处理(Derivative)、直接正交信号校正(DOSC)等预处理方法和基于遗传算法(GA)的有效波段选择方法来消除果皮对模型精度的影响.结果表明,苹果果皮对近红外光谱分析模型的预测能力有很大影响,但仅通过常规的光谱预处理方法(MSC、Derivative)很难有效消除.文章提出的遗传算法结合直接正交信号校正(GA-DOSC)方法能有效消除果皮的影响,不但使所建模型的波长点和最佳主因子数分别由1480和5降到36和1;其相关系数r由0.753提高到0.805,更重要的是模型的预测相对误差RSDp从16.71%显著下降到12.89%,并接近采用苹果果肉建模的预测性能(12.36%),达到了对苹果硬度的近红外无损检测要求. 相似文献