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921.
922.
基于密度泛函理论方法,本文开展了氦掺杂AlΣ3((111)/180°)晶界数值模拟拉伸试验.计算结果表明,He在晶界中最低杂质形成能为2.942 eV,偏析到晶界的偏析能为0.085 eV;在拉伸条件下,清洁Σ3晶界的理论拉伸强度为9.65 GPa,拉伸断裂从晶界界面开始;而He掺杂后,晶界的理论拉伸强度下降到7.14 GPa,在断裂发生前应力曲线中出现平台效应,拉伸断裂从包含He杂质的界面开始.通过对比键长和电荷密度分布,本文认为He的满壳层电子结构一方面导致了He与Al之间
关键词:
He
晶界
第一性原理计算
力学性质 相似文献
923.
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
924.
液氘在高压下有丰富的电学光学性质。利用反射率和相对介电函数关系并从广义极化角度出发初步建立了计算低Z材料电导率的简易模型;在神光-Ⅱ装置上利用第九路激光冲击加载液氘材料并测量了其在强激光冲击下的高压状态参数和反射率。结合上述理论模型和实验,研究了高压下液氘的电离度和电导率。结果表明,液氘在约70 GPa时的电导率约为2.87105 (Wm)-1,已呈现出较为明显的金属电导特性。显然,冲击加载下液氘从绝缘分子态开始电离并向金属氘转变发生在更低的压强。 相似文献
925.
The increasing use of nanopesticides has raised concerns about their effects on crop plants and the impact of human health as well as ecological effects. While increased uptake of metal ions has been observed before, to date, very few studies have demonstrated the presence of nanoparticles in edible tissues. Single-particle inductively coupled plasma–mass spectrometry (sp-ICP-MS) has been suggested as a powerful tool to detect inorganic nanoparticles (NPs) in environmental samples. Here, we exposed edible plant tissues from lettuce, kale, and collard green to nano-CuO, simulating its use as a nanopesticide. We applied sp-ICP-MS to demonstrate the presence of nanoparticles, both in the water used to rinse crop leaf surfaces exposed to nano-CuO and within the leaf tissues. Lettuces retained the highest amounts of nCuO NPs on the leaf surface, followed by collard green and then kale. Surface hydrophilicity and roughness of the leaf surfaces played an important role in retaining nano-CuO. The results indicate that most of the nanoparticles are removed via washing, but that a certain fraction is taken up by the leaves and can result in human exposure, albeit at low levels. 相似文献
926.
Novel feather duster-like nickel sulfide (NiS) @ molybdenum sulfide (MoS2) with hierarchical array structure is synthesized via a simple one-step hydrothermal method, in which a major structure of rod-like NiS in the center and a secondary structure of MoS2 nanosheets with a thickness of about 15–55 nm on the surface. The feather duster-like NiS@MoS2 is employed as the counter electrode (CE) material for the dye-sensitized solar cell (DSSC), which exhibits superior electrocatalytic activity due to its feather duster-like hierarchical array structure can not only support the fast electron transfer and electrolyte diffusion channels, but also can provide high specific surface area (238.19 m2 g?1) with abundant active catalytic sites and large electron injection efficiency from CE to electrolyte. The DSSC based on the NiS@MoS2 CE achieves a competitive photoelectric conversion efficiency of 8.58%, which is higher than that of the NiS (7.13%), MoS2 (7.33%), and Pt (8.16%) CEs under the same conditions. 相似文献
927.
This work presents the synthesis of magnetite nanoparticle (MNP) coated with poly(N,N-diethylaminoethyl methacrylate)-b-poly(N-isopropyl acrylamide-st-thiolactone acrylamide) (PDEAEMA-b-P(NIPAAm-st-TlaAm) copolymer and its use in controlled drug release and bio-conjugation. TlaAm units in the copolymer were ring-opened with various alkyl amines to form thiol groups (-SH), followed by thiol-ene coupling reactions with acrylamide-coated MNP and then quaternized to obtain cationic copolymer-MNP assemblies (the size <?200 nm/cluster). The use of alkyl amines having various chain lengths (e.g., 1-propylamine, 1-octylamine, or 1-dodecylamine) in the nucleophilic ring-opening reactions of the thiolactone rings affected their magnetic separation ability, water dispersibility, and release rate of doxorubicin model drug. In all cases, when increasing the temperature, they showed a thermo-responsive behavior as indicated by the decrease in hydrodynamic size and the accelerated drug release rate. These copolymer-MNP assemblies could be used as a novel platform with thermal-triggering controlled drug release and capability for adsorption with any negatively charged biomolecules. 相似文献
928.
Tonghui Yang Xiaolan Liu Yanli Ding Shihua Zhao Naiqiang Yin 《Journal of nanoparticle research》2018,20(8):207
In this work, ZnO nanorod/Cu2O composite nanostructure solar cells were prepared using hydrothermal growth and electrodeposition. The CdS layer was added between ZnO and Cu2O to suppress carrier reverse recombination. Nondestructive interface deposition methods were employed to prepare CdS and Cu2O functional layers. The CdS layers were unconventionally deposited in non-alkaline solution, which can inhibit etching on the ZnO surface, and Cu2O layers were electrodeposited in ZnO-buffered alkaline solution which can also inhibit etching on the ZnO surface. Finally, the performance of solar cells was improved by adding a highly resistive CdS intermediate layer between ZnO and Cu2O layers. This work demonstrated the nondestructive interface approach of chemical solution deposition of functional layers on ZnO and possibilities for further improvements to the performance of Cu2O-based nanostructure solar cells with the addition of an intermediated layer. 相似文献
929.
Tian Yu Tang Sheng Qiang Ren Yuan Liu Jing Quan Zhang Cai Liu Li Li Wu Wen Wu Wang Wei Li Liang Huan Feng 《Russian Journal of Physical Chemistry B, Focus on Physics》2018,12(3):503-509
Zn2SnO4 (ZTO) is a stable semiconductor in ZnO–SnO2 system and important transparent conducting oxide (TCO) predominantly used in optoelectronic devices. ZTO thin films were prepared by RF magnetron sputtering using Zn2SnO4 ceramic target in this paper. The effects of annealing temperatures and oxygen contents on characterization of ZTO thin films were studied. The results show that ZTO thin films prepared by RF magnetron sputtering are amorphous with an optical band gap of 3.22 eV. After annealing at 650°C in Ar atmosphere for 40 min, ZTO films possess a spinel structure with an optical band gap of 3.62 eV. The atomic force microscope (AFM) data of morphology reveals that the surface roughness of films is about 2 nm. The results of energy dispersive spectrometer (EDS) show that the concentration ratio of Zn to Sn is in the range from 1.44 to 1.57. The results of Hall-effect-measurement system reveal that the resistivity of films varies from 102 to 10–1 Ωcm, carrier concentration is about 1017 cm–3, and mobility ranges from 100 to 101 cm2 v–1 s–1. 相似文献
930.
In this paper, the stationary probability distribution (SPD) function and the mean first passage time (MFPT) are investigated in a tumor growth model driven by non-Gaussian noise which is introduced to mimic random fluctuations in the levels of the immune system. Results demonstrate the different transitions induced by the strength of non-Gaussian noise under different immune coefficients and the dual roles of non-Gaussian noise in promoting host protection against cancer and in facilitating tumor escape from immune destruction. Additionally, it can be discovered that increases in noise strength, the degree of departure from Gaussian noise, and the immune coefficient can accelerate the extinction of tumor cells. Numerical simulations are performed, and their results present good agreement with the theoretical results. 相似文献