On g-s-supplemented subgroups of finite groups

A subgroup H of a group G is said to be g-s-supplemented in G if there exists a subgroup K of G such that HK⊴G and H ∩ K ⩽ H _sG , where H_sG is the largest s-permutable subgroup of G contained in H. By using this new concept, we establish some new criteria for a group G to be soluble.     

Multiple Anti‐Counterfeiting Guarantees from a Simple Tetraphenylethylene Derivative – High‐Contrasted and Multi‐State Mechanochromism and Photochromism

Herein the novel tetraphenylethylene (TPE) derivative 1 was designed with an integration of aggregation‐induced emission (AIE), multi‐state mechanochromism and self‐recovery photochromism. The molecule was susceptible to grinding, heating and vapor fuming and showed corresponding transition of its emission colors. The heated powder or single crystal of 1 exhibited reversible photochromism. After a short period of UV irradiation, it showed a bright red color, but recovered to its original white appearance within 1 min. The photochromism is due to the formation of photocyclization intermediates upon UV irradiation, while the eversible mechanochromism is attributed to the weak molecular interactions derived from head‐to‐tail stacking of the molecules. This reversible multi‐state, high‐contrasted and rapid responsive mechanochromic and photochromic property cooperatively provide double enhancement of a multimode guarantee in advanced anti‐counterfeiting.     

Generation of Nanoparticle,Atomic‐Cluster,and Single‐Atom Cobalt Catalysts from Zeolitic Imidazole Frameworks by Spatial Isolation and Their Use in Zinc–Air Batteries

The size effect of transition‐metal nanoparticles on electrocatalytic performance remains ambiguous especially when decreasing the size to the atomic level. Herein, we report the spatial isolation of cobalt species on the atomic scale, which was achieved by tuning the zinc dopant content in predesigned bimetallic Zn/Co zeolitic imidazole frameworks (ZnCo‐ZIFs), and led to the synthesis of nanoparticles, atomic clusters, and single atoms of Co catalysts on N‐doped porous carbon. This synthetic strategy allowed an investigation of the size effect on electrochemical behavior from nanometer to Ångström dimensions. Single‐atom Co catalysts showed superior bifunctional ORR/OER activity, durability, and reversibility in Zn–air batteries compared with the other derivatives and noble‐metal Pt/C+RuO₂, which was attributed to the high reactivity and stability of isolated single Co atoms. Our findings open up a new avenue to regulate the metal particle size and catalytic performance of MOF derivatives.     

钢筋混凝土对边简支板的爆炸试验

爆炸载荷作用下钢筋混凝土板是建筑结构破坏的薄弱环节,其破坏还导致结构整体刚度 退化和动力响应升级. 以对边简支钢筋混凝土板为试验对象,在两个相同的试样上进行独立 的爆炸试验,观测钢筋混凝土板在弹性区动力响应和塑性区破坏特征,为碳纤维加固钢筋混 凝土板抗爆炸试验研究提供有效的数据和参照,实验现象和数据可供同类研究参考.     

十二烷基本磺酸钠对2-(2-苯骈噻唑偶氮)-5-二甲氨基苯甲酸与镍反应影响的研究

本文利用超过滤法研究了Ni(Ⅱ)-BTAMB-SDBS体系的热力学性质,同时利用光度法研究了体系的动力学性质,讨论了表面活性剂与各组份之间的作用情况,结果表明,胶束对显色反应的“催化”作用,实质上是由胶束对过量试剂的“富集”作用引起,BTAMB几乎不被SDBS富集,故体系中观察不到这种催化作用,并且在通常所涉及的表面活性剂用量范围内,不存在过量胶束使显色体系腿色的效应,这与通常的表面活性剂增敏体系相比,有其特殊之处.     

On c-Normal Subgroups of Finite Groups

A subgroup H is said to be c-normal in a group G if there exists a normal subgroup K of G such that G = HK and H K is contained in H_G, where H_G is the maximal normal subgroup of G. We determine the structures of some groups in which some primary subgroups is c-normal.AMS Mathematics Subject Classification (2000) 20D10 20D20     

The first chiral organometallic triangle for asymmetric catalysis

A family of chiral organometallic triangles based on cis-Pt(PEt3)2 metallocorners and enantiopure atropisomeric bis(alkynyl) bridging ligands (L1-4) has been synthesized and characterized by 1H, 13C{1H}, and 31P{1H} NMR, UV-vis, and circular dichroism (CD) spectroscopies, FAB and MALDI-TOF mass spectrometry, and microanalysis. Metallocycle 4 which contains three 1,1'-bi-2-naphthol functionalities in combination with Ti(iOPr)4 has been shown to be an excellent catalyst for highly enantioselective additions of diethylzinc to aromatic aldehydes to afford chiral secondary alcohols. This research illustrates the potential of generating novel functional materials on the basis of supramolecular chemistry.     

G-Covering Systems of Subgroups for Classes of p-Supersoluble and p-Nilpotent Finite Groups

Let be a class of groups. Given a group G, assign to G some set of its subgroups =(G). We say that is a G-covering system of subgroups for (or, in other words, an -covering system of subgroups in G) if G whenever either =Ø or Ø and every subgroup in belongs to . We find the systems of subgroups in the class of finite soluble groups G which are simultaneously the G-covering systems of subgroups for the classes of p-supersoluble and p-nilpotent groups.     

Direct algorithm for computation of derivatives of the Daubechies basis functions

We extend the direct algorithm for computing the derivatives of the compactly supported Daubechies N-vanishing-moment basis functions. The method yields exact values at dyadic rationals for the nth derivative (0  n  N − 1) of the basis functions, when it exists. Example results are shown for the first derivatives of the basis functions from the Daubechies N-vanishing-moment extremal phase orthonormal family (for N = 3, 4, and 5), and the CDF(2, N) spline-based biorthogonal family (for N = 6, 8, and 10).