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101.
Dr. Tetsuo Tsuchiya Dr. Tomohiko Nakajima Yuko Uzawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(42):9261-9276
This review summarizes the use of photoreactions that replace conventional heating processes for growing oxide thin films from chemical solutions. In particular, this review outlines key variables in photoreactions that affect epitaxial and polycrystalline thin film growth, including precursor materials, laser wavelength, laser fluence, and carbon. In addition, the features of the photoreaction process that can be controlled at a low temperature by oxygen non-stoichiometry are examined. Likewise, functions that are neither achieved by developing a gradient structure nor controlled by a thermal equilibrium reaction are detailed. Two new concepts are presented, known as photoreaction of nanoparticles (PRNP) and photoreaction of a hybrid solutions (PRHS), in which crystal nuclei are pre-dispersed in a metal–organic compound film. This method has successfully produced flexible phosphor films used as resistor or thermistor electronic components. Finally, thin film growth using different light sources such as flash lamps and femtosecond lasers (fs) is explored. 相似文献
102.
Prof. Dr. Bernhard Kräutler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15438-15445
The recently delineated structure- and reactivity-based concept of antivitamins B12 has begun to bear fruit by the generation, and study, of a range of such B12-dummies, either vitamin B12-derived, or transition metal analogues that also represent potential antivitamins B12 or specific B12-antimetabolites. As reviewed here, this has opened up new research avenues in organometallic B12-chemistry and bioinorganic coordination chemistry. Exploratory studies with antivitamins B12 have, furthermore, revealed some of their potential, as pharmacologically interesting compounds, for inducing B12-deficiency in a range of organisms, from hospital resistant bacteria to laboratory mice. The derived capacity of antivitamins B12 to induce functional B12-deficiency in mammalian cells and organs also suggest their valuable potential as growth inhibitors of cancerous human and animal cells. 相似文献
103.
Piotr Bajger Mariusz Bodzioch Urszula Foryś 《Mathematical Methods in the Applied Sciences》2020,43(18):10671-10689
We consider a two-compartment model of chemotherapy resistant tumour growth under angiogenic signalling. Our model is based on the one proposed by Hahnfeldt et al. (1999), but we divide tumour cells into sensitive and resistant subpopulations. We study the influence of antiangiogenic treatment in combination with chemotherapy. The main goal is to investigate how sensitive are the theoretically optimal protocols to changes in parameters quantifying the interactions between tumour cells in the sensitive and resistant compartments, that is, the competition coefficients and mutation rates, and whether inclusion of an antiangiogenic treatment affects these results. Global existence and positivity of solutions and bifurcations (including bistability and hysteresis) with respect to the chemotherapy dose are studied. We assume that the antiangiogenic agents are supplied indefinitely and at a constant rate. Two optimisation problems are then considered. In the first problem a constant, indefinite chemotherapy dose is optimised to maximise the time needed for the tumour to reach a critical (fatal) volume. It is shown that maximum survival time is generally obtained for intermediate drug dose. Moreover, the competition coefficients have a more visible influence on survival time than the mutation rates. In the second problem, an optimal dosage over a short, 30-day time period, is found. A novel, explicit running penalty for drug resistance is included in the objective functional. It is concluded that, after an initial full-dose interval, an administration of intermediate dose is optimal over a broad range of parameters. Moreover, mutation rates play an important role in deciding which short-term protocol is optimal. These results are independent of whether antiangiogenic treatment is applied or not. 相似文献
104.
论文针对中密度聚乙烯材料(MDPE),采用平板试样进行了I型疲劳裂纹扩展和单次过载下裂纹扩展试验.发现与金属材料类似,单次拉伸过载对聚乙烯(PE)的疲劳裂纹扩展有明显的迟滞作用,降低了裂纹扩展速率.试验还通过变载荷刻线法获取疲劳裂纹扩展前缘的实际形貌和变化规律,对常规变载荷刻线方法进行了调整和验证,其修正方法对高分子材料的疲劳裂纹扩展前缘刻线具有较好的效果.通过观察发现含楔形塑性区的裂尖钝化是裂纹迟滞的主要原因.过载引入的塑性区内残余应力对裂纹迟滞也起了重要作用.论文利用Dugdale模型计算了塑性区尺寸,使用基于残余应力的Wheeler模型对过载迟滞进行了很好的拟合. 相似文献
105.
Multiphase flows are critical components of many physical systems; however, numerical models of multiphase flows with large parameter gradients can be challenging. Here, two different numerical methods, volume of fluid (VOF) and smoothed particle hydrodynamics (SPH), are used to model the buoyant rise of isolated gas bubbles through quiescent fluids for a range of Bond and Reynolds numbers. The VOF is an Eulerian grid–based method, whereas the SPH is Lagrangian and mesh free. Each method has unique strengths and weaknesses, and a comparison of the two approaches as applied to multiphase phenomena has not previously been performed. The VOF and SPH simulations are compared, verified, and validated. Results using two-dimensional VOF and SPH simulations are similar to each other and are able to reproduce numerical benchmarks and experimental results for sufficiently large Morton and Reynolds numbers. It is also shown that at low Reynolds numbers, the two methods, SPH and VOF, diverge in the transient regime of the bubble rise. Regimes that require simulations capable of representing three-dimensional drag are identified as well as regimes in which results from VOF and SPH diverge. 相似文献
106.
Marie-Claude Viallon 《国际流体数值方法杂志》2020,92(5):391-421
The heat equation is solved by using a finite volume discretization in a domain that consists of a two-dimensional central node and several one-dimensional outgoing branches. Several interface connection options to match the submodels set on the node and on the branches, with or without continuity, are looked at. For each of them, a monolithic scheme is defined, and existence and uniqueness of the solution is proved. New schemes are deduced, which are obtained through domain decomposition methods in the form of interface systems, with one or two unknowns per interface. A comparative systematic study is carried out from an algebraic and numerical point of view according to the interface conditions: Dirichlet, Neumann, or Robin. An efficient diagonal preconditioning is proposed. 相似文献
107.
Manuel Bernard Ghislain Lartigue Guillaume Balarac Vincent Moureau Guillaume Puigt 《国际流体数值方法杂志》2020,92(11):1551-1583
In this article, a new framework to design high-order approximations in the context of node-centered finite volumes on simplicial meshes is proposed. The major novelty of this method is that it relies on very simple and compact differential operators, which is a critical point to achieve good performances in the High-performance computing context. This method is based on deconvolution between nodal and volume-average values, which can be conducted to any order. The interest of the new method is illustrated through three different applications: mesh-to-mesh interpolation, levelset curvature computation, and numerical scheme for convection. Higher order can also be achieved within the present framework by introducing high-rank tensors. Although these tensors feature much symmetries, their manipulation can quickly become an overwhelming task. For this reason and without loss of generality, the present articles are limited to third-order expansion. This method, although tightly connected to the k-exact schemes theory, does not rely on successive corrections: the high-order property is obtained in a single operation, which makes them more attractive in terms of performances. 相似文献
108.
Minghao Xie Zhiheng Lyu Ruhui Chen Prof. Dr. Younan Xia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15636-15642
Oleic acid (OAc) is commonly used as a surfactant and/or solvent for the oil-phase synthesis of metal nanocrystals but its explicit roles are yet to be resolved. Here, we report a systematic study of this problem by focusing on a synthesis that simply involves heating of Pt(acac)2 in OAc for the generation of Pt nanocrystals. When heated at 80 °C, the ligand exchange between Pt(acac)2 and OAc leads to the formation of a PtII–oleate complex that serves as the actual precursor to Pt atoms. Upon increasing the temperature to 120 °C, the decarbonylation of OAc produces CO, which can act as a reducing agent for the generation of Pt atoms and thus formation of nuclei. Afterwards, several catalytic reactions can take place on the surface of the Pt nuclei to produce more CO, which also serves as a capping agent for the formation of Pt nanocrystals enclosed by {100} facets. The emergence of Pt nanocrystals further promotes the autocatalytic surface reduction of PtII precursor to enable the continuation of growth. This work not only elucidates the critical roles of OAc at different stages in a synthesis of Pt nanocrystals, but also represents a pivotal step forward toward the rational synthesis of metal nanocrystals. 相似文献
109.
K Narasimha Swamy 《Pramana》1975,4(4):175-183
The excess properties of mixing were calculated for seven systems Ar-CH4; Ar-N2; Ar-O2; Ar-CO; CO-CH4; O2-N2; N2-CO, using the Caranhan and Starling equation of state of rigid spheres and the Longuet-Higgins and Widom model. Two sets
of calculations were done one using the experimentalG
E
to calculateS
E
,H
E
andV
E
, and the other making use of Miller’s cross parameter values. The calculated values are compared with those of Snider and
Herrington and Miller’s values and also with the experimental values. The agreement was found to be good. 相似文献
110.
P.V. Jyothy 《Journal of Physics and Chemistry of Solids》2009,70(6):927-930
Cadmium sulfide semiconductor nanocrystals along with dysprosium ions were incorporated in silica xerogels through sol-gel route. The fluorescence properties were analyzed for samples annealed at different temperatures. The incorporation of the CdS semiconductors as nanocrystallites was confirmed from the HRTEM measurements. The fluorescence intensities were compared for Dy3+, CdS and Dy3+/CdS-doped silica xerogels. Enhanced blue emission was observed for codoped samples annealed up to 100 °C. 相似文献