排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
2.
We demonstrate the existence of homogeneity properties of the singular part of the free energy at the tricritical point of a soluble magneto-elastic model. The free energy is only homogeneous when viewed as a function of the appropriate curvilinear coordinates in the space of independent thermodynamic variables. It is not homogeneous as a function of the linear coordinates of either Griffiths of Riedel. The implications of this result for the general scaling theory of tricritical points are discussed. 相似文献
3.
Lois M. Muiva-Mutisya Yoseph Atilaw Matthias Heydenreich Andreas Koch Hoseah M. Akala Agnes C. Cheruiyot 《Natural product research》2018,32(12):1407-1414
The CH2Cl2/MeOH (1:1) extract of the aerial parts of Tephrosia subtriflora afforded a new flavanonol, named subtriflavanonol (1), along with the known flavanone spinoflavanone B, and the known flavanonols MS-II (2) and mundulinol. The structures were elucidated by the use of NMR spectroscopy and mass spectrometry. The absolute configuration of the flavanonols was determined based on quantum chemical ECD calculations. In the antiplasmodial assay, compound 2 showed the highest activity against chloroquine-sensitive Plasmodium falciparum reference clones (D6 and 3D7), artemisinin-sensitive isolate (F32-TEM) as well as field isolate (KSM 009) with IC50 values 1.4–4.6 μM without significant cytotoxicity against Vero and HEp2 cell lines (IC50 > 100 μM). The new compound (1) showed weak antiplasmodial activity, IC50 12.5–24.2 μM, but also showed selective anticancer activity against HEp2 cell line (CC50 16.9 μM). 相似文献
4.
We examine the soluble magnetoelastic Ising model developed by Baker and Essam and give a detailed discussion of its thermodynamic properties. Particular attention is devoted to the properties of the magnetic phase transition at zero field, which is found to be either first order or second order, depending on whether the experiment is performed at negative or positive pressure.Part of this work was done while L. G. was visiting Tel Aviv University. Research supported by National Science Foundation Grant No. GP. 16025 to L. G. 相似文献
5.
We show that the one- and two-dimensional ideal Bose gases undergo a phase transition if the temperature is lowered at constant pressure. At the pressure-dependent transition temperature Tc (P) and in their thermodynamic limit the specific heat at constant pressure cp and the particle densityn diverge, the entropyS and specific heat at constant volumec v fall off sharply but continuously to zero, and the fraction of particles in the ground state N0/N jumps discontinuously from zero to one. This Bose-Einstein condensation provides a remarkable example of a transition which has most of the properties of a second-order phase transition, except that the order parameter is discontinuous. The nature of the condensed state is described in the large but finiteN regime, and the width of the transition region is estimated. The effects of interactions in real one- and two-dimensional Bose systems and recent experiments on submonolayer helium films are discussed briefly. 相似文献
6.
Bob A. Howell Yoseph G. Daniel 《Phosphorus, sulfur, and silicon and the related elements》2020,195(8):638-643
AbstractIsosorbide is a diether diol readily available from starch, an abundant, renewable biomaterial. Because of its structure and functionality, it may serve as a base for the development of nontoxic polymer additives, particularly flame retardants. Conversion of one of the hydroxyl groups to a diphenylphosphato moiety followed by conversion of the other to an acrylate affords isomeric vinyl monomers suitable for copolymerization with a variety of monomers to generate flame-retardant polymers. 相似文献
7.
Yoseph Imry 《Journal of statistical physics》1984,34(5-6):849-862
The various theoretical considerations for the effects of quenched random fields (RF) on second-order transitions as well as the experimental situation are briefly reviewed. Some of the physical realizations of the RF models are discussed, with an emphasis on solid-state first-order transitions in impure systems. The physical arguments for the RF effects in the bulk as well as on phase interfaces are discussed. In the latter case it is suggested that scattering experiments can probe the details of the interface fluctuations. The role of long relaxation times and metastability in Ising RF systems is emphasized.Research at Tel Aviv University partially supported by the U.S.-Israel Binational Science Foundation (BSF), Jerusalem, Israel. 相似文献
8.
Dr. Juliana S. A. Carneiro Dr. Giada Innocenti Hyun June Moon Yoseph Guta Laura Proaño Prof. Dr. Carsten Sievers Dr. Miles A. Sakwa-Novak Dr. Eric W. Ping Prof. Dr. Christopher W. Jones 《Angewandte Chemie (International ed. in English)》2023,62(24):e202302887
Direct air capture (DAC) processes for extraction of CO2 from ambient air are unique among chemical processes in that they operate outdoors with minimal feed pretreatments. Here, the impact of humidity on the oxidative degradation of a prototypical solid supported amine sorbent, poly(ethylenimine) (PEI) supported on Al2O3, is explored in detail. By combining CO2 adsorption measurements, oxidative degradation rates, elemental analyses, solid-state NMR and in situ IR spectroscopic analysis in conjunction with 18O labeling of water, a comprehensive picture of sorbent oxidation is achieved under accelerated conditions. We demonstrated that the presence of water vapor can play an important role in accelerating the degradation reactions. From the study we inferred the identity and kinetics of formation of the major oxidative products, and the role(s) of humidity. Our data are consistent with a radical mediated autooxidative degradation mechanism. 相似文献
9.
Dr. Qiang Wen Dr. Naveen Malik Dr. Yoseph Addadi Maren Weißenfels Vivek Singh Dr. Linda J. W. Shimon Dr. Michal Lahav Prof. Milko E. van der Boom 《Angewandte Chemie (International ed. in English)》2023,62(4):e202214041
In this study, the precise positioning and alignment of arrays of two different guest molecules in a crystalline host matrix has been engineered and resulted in new optically active materials. Sub-nm differences in the diameters of two types of 1D channels are sufficient for size-selective inclusion of dyes. Energy transport occurs between the arrays of different dyes that are included in parallel-positioned nanochannels by Förster resonance energy transfer (FRET). The color of individual micro-sized crystals are dependent on their relative position under polarized light. This angular-dependent behavior is a result of the geometrically constrained orientation of the dyes by the crystallographic packing of the host matrix and is concentration dependent. 相似文献
10.
We provide the first theoretical proof of the spectrum of orders n for which circulant weighing matrices with weight 9 exist. This spectrum consists of those positive integers n, which are multiples of 13 or 24. We actually characterize the “minimal” examples which exist for orders 13, 26, or 24. 相似文献