Recent Developments in Robust Portfolios with a Worst-Case Approach

Robust models have a major role in portfolio optimization for resolving the sensitivity issue of the classical mean–variance model. In this paper, we survey developments of worst-case optimization while focusing on approaches for constructing robust portfolios. In addition to the robust formulations for the Markowitz model, we review work on deriving robust counterparts for value-at-risk and conditional value-at-risk problems as well as methods for combining uncertainty in factor models. Recent findings on properties of robust portfolios are introduced, and we conclude by presenting our thoughts on future research directions.     

Measurement of <Superscript>99</Superscript>Mo production cross-section from the <Superscript>100</Superscript>Mo(n,2n) reaction with quasi monoenergetic neutron based on the <Superscript>9</Superscript>Be(p,n) reaction

The production cross-section of the medical isotope, ⁹⁹Mo from the enriched ¹⁰⁰Mo(n,2n) reaction with the average neutron energies of 21.9 and 26.5 MeV has been determined for the first time by using an off-line γ-ray spectrometric technique. The average neutron energies were generated by using the ⁹Be(p,n) reaction with the proton energies of 35 and 45 MeV from the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences (KIRAMS) at Seoul, South Korea. The ¹⁰⁰Mo(n,2n) reaction cross-section as a function of neutron energy was also calculated theoretically by using the computer code TALYS-1.8 and EMPIRE-3.2 Malta. The experimental results are in close agreement with the theoretical values from TALYS-1.8. However, the present data at the neutron energy of 21.9 MeV is slightly lower and at 26.5 MeV is higher than the values from EMPIRE-3.2 Malta.     

Synthesis and visible light photocatalytic activity of Ag spot-coated TiO2–60 wt% SrO composite powders

Nano-sized TiO₂–60 wt% SrO composite powders were synthesized from titanium isopropoxide and Sr(OH)₂·8H₂O by use of a sol–gel method. Ag spot-coated TiO₂–60 wt% SrO composite powders containing 3, 5, or 7 wt% Ag were synthesized by hydrothermal-assisted attachment, by use of Ag hydrosol in a high-pressure bomb at 250 °C and 450 psi. Nano-sized Ag particles approximately 5–25 nm in diameter adhered to the TiO₂–60 wt% SrO₂ composite powders. The photocatalytic activity of Ag spot-coated TiO₂–SrO powders in the degradation of phenol showed that all were highly active when irradiated with UV light. TiO₂–60 wt% SrO composite powder spot-coated with 5 wt% Ag was more photocatalytically active under visible light than TiO₂–SrO composite powder.     

Real Hypersurfaces in Complex Two-Plane Grassmannians with GTW Reeb Lie Derivative Structure Jacobi Operator

Mediterranean Journal of Mathematics - Using GTW connection, we considered a real hypersurface M in a complex two-plane Grassmannian $${G_{2}({\mathbb{C}}^{m+2})}$$ when the GTW Reeb Lie derivative...     

采用金属有机骨架材料M(HBTC)(4,4'-bipy)·3DMF(M=Ni,Co,Zn)催化CO_2与环氧丙烷的环加成反应（英文）

采用溶剂热法合成了三种M(HBTC)(4,4’-bipy)·3DMF(M=Ni,Co,Zn,HBTC=1,3,5-均苯三甲酸,4,4’-bipy=4,4′-联吡啶)结构的支柱层金属有机骨架材料(MOFs).首次采用溶剂热和微波法合成了Zn(HBTC)(4,4’-bipy)·3DMF,并采用多种物理化学方法对其进行了表征.M(HBTC)(4,4’-bipy)·3DMF中包含有M2+离子的蜂窝网格层和BTC单元,BTC单元与4,4’-联吡啶柱进一步交联形成三维多孔骨架材料.在采用烷基铵卤化物作为助催化剂和无溶剂的条件下,所有MOFs材料均对催化固定CO_2与环氧化合物环加成制备环状碳酸酯反应表现出非常好的协同催化性能,其催化活性高低顺序为:ZnCoNi,这可通过酸-碱双功能特性进行解释.采用微波法合成的Zn(HBTC)(4,4’-bipy)·3DMF材料表现出与常规催化剂相似的物理化学性质和催化性能.考察了不同制备参数的影响和材料的重复使用性能,并提出了该反应的可能机理