Measurement of the magnetic field-dependent refractive index of magnetic fluids in bulk

An optical alignment-free and highly accurate method is employed to measure the magnetic field-dependent refractive index of magnetic fluid(MF) in bulk.The measured refractive index decreases significantly with the increasing magnetic strength and then tends to saturate in the high intensity range.By applying a tunable magnetic field ranging between 0 and 1661 Oe,the maximum shift of the refractive index of MF in bulk iS found to be 0.0231.     

The classical monotone convergence theorem of Beppo Levi fails in noncommutative -spaces

Let be a complex Hilbert space and let be a von Neumann algebra over equipped with a faithful, normal state . Then is a prehilbert space with respect to the inner product , whose completion is given by the Gelfand-Naimark-Segal representation theorem, according to which there exist a one-to-one -homomorphism of into the algebra of all bounded linear operators acting on and a cyclic, separating vector such that for all . Given any separable Hilbert space , we construct a faithful, normal state on and an increasing sequence of positive operators acting on such that is bounded, but fails to converge both bundlewise and in -norm. We also present an example of an increasing sequence of positive operators which has a subsequence converging both bundlewise and in -norm, but the whole sequence fails to converge in either sense. Finally, we observe that our results are linked to a previous one by R. V. Kadison.

     

Development and application of the intense slow positron beam at IHEP

This paper describes the development and application of an intense slow positron beam at IHEP with regard to its two main components.The Variable-Energy Positron Lifetime Spectroscopy (VEPLS) based on the pulsing system consisting of a chopper,a prebuncher and a buncher has been constructed in order to meet the needs of materials science development.At present,the time resolution of the VEPLS can easily reach about 386 ps with a peak-to-background ratio of about 600:1.A plugged-in 22Na positron source section for adjusting the newly built experimental station and for increasing the beam operation efficiency has been constructed.A slow positron beam with an intensity of 2.5x105 e+/s and the beam profile whose diameter is 10 mm has been obtained;the moderation efficiency of the tungsten mesh moderator reaches 5.1x 10-4 as calculated with an original positron source activity of 52 mCi.     

Stochastic rearrangement inequalities

We develop a unified theory for obtaining stochastic rearrangement inequalities and show how this theory may be applied in statistical contexts such as ranking problems, hypothesis testing, contamination models, and optimal assembly of systems.     

Global Minimization of Increasing Positively Homogeneous Functions over the Unit Simplex

In this paper we study a method for global optimization of increasing positively homogeneous functions over the unit simplex, which is a version of the cutting angle method. Some properties of the auxiliary subproblem are studied and a special algorithm for its solution is proposed. A cutting angle method based on this algorithm allows one to find an approximate solution of some problems of global optimization with 50 variables. Results of numerical experiments are discussed.     

Preserving the Rothschild–Stiglitz type increase in risk with background risk: A characterization

In order to generalize previous results by Li et al. (2016), Guo et al. (2016) extended the definition of the Rothschild–Stiglitz type of increase in risk to a background risk framework. They provided several sufficient conditions for such a ranking to hold, involving expectation dependence concepts. In this short note, the corresponding characterizations are established, based on the bivariate higher-degree increasing concave orders introduced by Denuit et al. (1999).     

Theoretical model of acoustic emission under mechanical loading of rocks in the maximum compaction region

A theoretical model of changes in acoustic emission activity in a geomaterial under continuous or stepwise mechanical loading is justified. Based on this model, the experimentally found laws of emission in the region of the maximum compaction of rock samples with different rates of mechanical loading of these samples are analyzed. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 4, pp. 145–152, July–August, 2006.     

拟序下非连续增算子新的广义不动点定理

运用序方法研究了拟序空间X中具A=CB型非连续增算子的广义不动点的存在性问题,证明了在拟序空间X中具A=CB型非连续增算子存在最小广义不动点和最大广义不动点.所得结果推广了相关结论.     

有限合作博弈的Shapley分配

以Myerson关于有限合作的图博弈模型为基础,结合经典合作博弈的相关结论,建立了有限合作博弈的Shapley分配,讨论了分配的相关性质.同时在支付函数满足链递增性的假设下,进一步研究了有限合作关系变化对收益分配的影响,给出了相关的研究结论.     

Locally Ordered Single-Atom Catalysts for Electrocatalysis

Single-atom catalysts manifest nearly 100 % atom utilization efficiency, well-defined active sites, and high selectivity. However, their practical applications are hindered by a low atom loading density, uncontrollable location, and ambiguous interaction with the support, thereby posing challenges to maximizing their electrocatalytic performance. To address these limitations, the ability to arrange randomly dispersed single atoms into locally ordered single-atom catalysts (LO-SACs) substantially influences the electronic effect between reactive sites and the support, the synergistic interaction among neighboring single atoms, the bonding energy of intermediates with reactive sites and the complexity of the mechanism. As such, it dramatically promotes reaction kinetics, reduces the energy barrier of the reaction, improves the performance of the catalyst and simplifies the reaction mechanism. In this review, firstly, we introduce a variety of compelling characteristics of LO-SACs as electrocatalysts. Subsequently, the synthetic strategies, characterization methods and applications of LO-SACs in electrocatalysis are discussed. Finally, the future opportunities and challenges are elaborated to encourage further exploration in this rapidly evolving field.