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101.
Nesreen Alzoghoul Alsmadi Aniket S. Wadajkar Weina Cui Kytai T. Nguyen 《Journal of nanoparticle research》2011,13(12):7177-7186
The objective of this research was to compare the effects of two different surfactants on the physicochemical properties of
thermo-responsive poly(N-isopropylacrylamide-acrylamide-allylamine) (PNIPAAm-AAm-AH)-coated magnetic nanoparticles (MNPs). Sodium dodecyl sulfate
(SDS) as a commonly used surfactant in nanoparticle formulation process and Pluronic F127 as an FDA approved material were
used as surfactants to synthesize PNIPAAm-AAm-AH-coated MNPs (PMNPs). The properties of PMNPs synthesized using SDS (PMNPs-SDS)
and PF127 (PMNPs-PF127) were compared in terms of size, polydispersity, surface charge, drug loading efficiency, drug release
profile, biocompatibility, cellular uptake, and ligand conjugation efficiency. These nanoparticles had a stable core–shell
structure with about a 100-nm diameter and were superparamagnetic in behavior with no difference in the magnetic properties
in both types of nanoparticles. In vitro cell studies showed that PMNPs-PF127 were more cytocompatible and taken up more by
prostate cancer cells than that of PMNPs-SDS. Cells internalized with these nanoparticles generated a dark negative contrast
in agarose phantoms for magnetic resonance imaging. Furthermore, a higher doxorubicin release at 40 °C was observed from PMNPs-PF127,
and the released drugs were pharmacologically active in killing cancer cells. Finally, surfactant type did not affect the
conjugation efficiency to the nanoparticles when folic acid was used as a targeting ligand model. These results indicate that
PF127 might be a better surfactant to form polymer-coated magnetic nanoparticles for targeted and controlled drug delivery. 相似文献
102.
An attempt is made to synthesize Nd2Co14C compound by mechanical alloying Nd16Co76B8−xCx (0x8) alloys and subsequent annealing. Phase formation and magnetic properties of Nd2Fe14B-type Nd16Co76B8−xCx alloys and their hydrides are investigated. The Nd2Co14(B,C) phase with Nd2Fe14B-type structure is formed for Nd16Co76B8−xCx (0x7) alloys, while NdCo7Cδ phase with TbCu7-type structure is observed in Nd16Co76C8 alloy. The lattice parameter c of the Nd2Co14(B,C) phase decreases with increasing the carbon content. A limit volume of the unit cell to form the Nd2Fe14B-type structure is estimated to be 0.870 nm3. The spin-reorientation temperature TSR increases with increasing the carbon content, due to an enhancement of magnetocrystalline anisotropy caused by carbon substitution for boron. After hydrogenation, the lattice expansion is observed for Nd16Co76B8−xCx (0x7) alloys. The spin-reorientation temperature of Nd16Co76B8−xCxHy (0x7) is much lower than that of the host alloys. Some structural and magnetic properties of hypothetic Nd2Co14C and Nd2Co14CHy compounds are estimated by extrapolation. 相似文献
103.
用时域有限差分法,给出光纤头近场区电场强度模的空间分布.讨论了当光纤纤芯分别取不同尺寸时,对此空间光场强度的影响.要想得到较大范围的暗中空光束,必须增加光纤纤芯尺寸.并且,对光纤纤芯尺寸取一较大值和光纤中空区域尺寸取一较小值时的情况进行讨论,可得在光纤头附近可以出现与光纤中空区域尺寸大小相当的暗斑(101 nm量级).但是,暗中空光束中背景光较强.为此,将光纤的空心设计为金属. 发现此时中心暗斑的背景光明显减弱,在近场区域可获得较为理想的暗中空光束.如进一步缩小光纤中空区域尺寸,可以在光纤头附近获得暗斑更小甚至纳米量级的暗中空光束.为获得一种纳米量级的暗中空光束提供一种方法. 相似文献
104.
透射光栅广泛应用于软X射线能谱测量.为了获得用于惯性约束聚变研究的透射光栅的各级衍射效率及其他参数,在北京同步辐射源上200—1600 eV能量范围内对其进行了标定,获得了透射光栅衍射效率的实验结果.扩展了透射光栅衍射效率的计算方法,提出了7边准梯形截面衍射效率计算模型.分析拟合了实验数据,理论结果与实验结果很好符合.得到了7边准梯形的透射光栅栅线截面结构.
关键词:
透射光栅
衍射效率
实验标定
光栅模型 相似文献
105.
Huan
Zheng Guangwei Yuan Xia Cui 《Numerical Methods for Partial Differential Equations》2020,36(6):1845-1867
A fully implicit finite difference (FIFD) scheme with second-order space–time accuracy is studied for a nonlinear diffusion equation with general capacity term. A new reasoning procedure is introduced to overcome difficulties caused by the nonlinearity of the capacity term and the diffusion operator in the theoretical analysis. The existence of the FIFD solution is investigated at first which plays an important role in the analysis. It is established by choosing a new test function to bound the solution and its temporal and spatial difference quotients in suitable norms in the fixed point arguments, which is different from the traditional way. Based on these bounds, other fundamental properties of the scheme are rigorously analyzed consequently. It shows that the scheme is uniquely solvable, unconditionally stable, and convergent with second-order space–time accuracy in L∞(L2) and L∞(H1) norms. The theoretical analysis adapts to both one- and multidimensional problems, and can be extended to schemes with first-order time accuracy. Numerical tests are provided to verify the theoretical results and highlight the high accuracy of the second-order space–time accurate scheme. The reasoning techniques can be extended to a broad family of discrete schemes for nonlinear problems with capacity terms. 相似文献
106.
Using the nonequilibrium Keldysh Green's function technique, the Fano effect of a parallel-coupled triple Rashba quantum dot system is investigated. The conductance as a function of electron energy is numerically calculated. Compared with the case of a parallel-coupled double quantum dot system, two additional Fano resonance peaks occur in the conductance spectrum. By adjusting the structural parameters, the two Fano resonance peaks may change into the resonance peaks. In addition, the influence of Rashba spin-orbit interaction on the conductance is studied. 相似文献
107.
Di Yuan Jun-Long Tian Fang Lin Dong-Wei Ma Jing Zhang Hai-Tao Cui Yi Xiao 《Frontiers of Physics》2018,13(3):130504
In this study we investigate the collective behavior of the generalized Kuramoto model with an external pinning force in which oscillators with positive and negative coupling strengths are conformists and contrarians, respectively. We focus on a situation in which the natural frequencies of the oscillators follow a uniform probability density. By numerically simulating the model, it is shown that the model supports multistable synchronized states such as a traveling wave state, π state and periodic synchronous state: an oscillating π state. The oscillating π state may be characterized by the phase distribution oscillating in a confined region and the phase difference between conformists and contrarians oscillating around π periodically. In addition, we present the parameter space of the oscillating π state and traveling wave state of the model. 相似文献
108.
An active Q-switched diode-end-pumped Nd:YAG laser is reported with 2.9 W output power on the 4F3/2 → 4I9/2 transitions at a pump power of 24 W. With intracavity frequency doubling using a 20-mm-long LBO, a maximum blue output power of 2.25 W is achieved at a repetition rate of 23 kHz. The conversion efficiency from the corresponding Q-switched fundamental output to blue output is 96%. The peak power of the Q-switched blue pulse is up to 610 W with 160 ns pulse width. The fluctuation of the blue output power is less than 4.0% at the maximum output power. 相似文献
109.
The aim of this work is to study the effects of duty ratio on the growth mechanism of the ceramic coatings on Ti-6Al-4V alloy prepared by pulsed single-polar MPO at 50 Hz in NaAlO2 solution. The phase composition of the coatings was studied by X-ray diffraction, and the morphology and the element distribution in the coating were examined through scanning electron microscopy and energy dispersive spectroscopy. The thickness of the coatings was measured by eddy current coating thickness gauge. The corrosion resistance of the coated samples was examined by linear sweep voltammetry technique in 3.5% NaCl solution. The changes of the duty ratio (D) of the anode process led to the changes of the mode of the spark discharge during the pulsed single-polar MPO process, which further influenced the structure and the morphology of the ceramic coatings. The coatings prepared at D = 10% were composed of a large amount of Al2TiO5 and a little γ-Al2O3 while the coatings prepared at D = 45% were mainly composed of α-Al2O3 and γ-Al2O3. The coating thickness and the roughness were both increased with the increasing D due to the formation of Al2O3. The formation of Al2TiO5 resulted from the spark discharge due to the breakdown of the oxide film, while the formation of Al2O3 resulted from the spark discharge due to the breakdown of the vapor envelope. The ceramic coatings improved the corrosion resistance of Ti-6Al-4V alloy. And the surface morphology and the coating thickness determined the corrosion resistance of the coated samples prepared at D = 45% was better than that of the coated samples prepared at D = 10%. 相似文献
110.
研究了基于InP基的In0.65Ga0.35As/In0.52Al0.48As赝型高迁移率晶体管材料中纵向磁电阻的Shubnikov-deHaas(SdH)振荡效应和霍耳效应,通过对纵向磁电阻SdH振荡的快速傅里叶变换分析,获得了各子带电子的浓度,并因此求得了各子带能级相对于费米能级的位置.联立求解Schrdinger方程和Poisson方程,自洽计算了样品的导带形状、载流子浓度分布以及各子带能级和费米能级位置.理论计算和实验结果很好符合.实验和理论计算均表明,势垒层的掺杂电子几乎全部转移到了量子阱中,转移率在95%以上. 相似文献