Synthesis of new aryl substituted furan-2(5H)-ones using the Suzuki-Miyaura reaction

A series of novel 5-arylidenefuran-2(5H)-ones and 5-arylidene-4-arylfuran-2(5H)-ones were synthesized via the Suzuki-Miyaura reactions of fimbrolide derivatives 5-(bromomethylene)furan-2(5H)-one and 4-bromo-5-(bromomethylene)furan-2(5H)-one, respectively. A regioselective Suzuki-Miyaura reaction on 4-bromo-5-(bromomethylene)furan-2(5H)-one allowed the synthesis of unsymmetrically substituted 5-arylidene-4-arylfuran-2(5H)-ones. The crystal structure of the intermediate 5-arylidene-4-bromofuran-2(5H)-one revealed interesting Br?O halogen bonding.     

Quadratic bottleneck knapsack problems

In this paper we study the quadratic bottleneck knapsack problem (QBKP) from an algorithmic point of view. QBKP is shown to be NP-hard and it does not admit polynomial time ?-approximation algorithms for any ?>0 (unless P=NP). We then provide exact and heuristic algorithms to solve the problem and also identify polynomially solvable special cases. Results of extensive computational experiments are reported which show that our algorithms can solve QBKP of reasonably large size and produce good quality solutions very quickly. Several variations of QBKP are also discussed.     

Micro-punching process based on spallation delamination induced by laser driven-flyer

In this article, we proposed a micro-punching process for microstructure on films based on laser driven-flyer induced spallation delamination phenomenon at the interface between a film and its substrate. To validate such a micro-punching process, a series of experiments were carried out for fabrication of microstructures on Au films coated on K9 glass substrates and polyimide substrate. Results show that through such a punching process, the microstructure on Au films can be fabricated efficiently and the spatial resolution is able to reach micron level. Moreover, we found that this method was more suitable for films coated on soft substrates rather than that coated on brittle substrates due to the additional destruction of the brittle substrate. This micro-punching process has a wide range of potential application in microfluidic devices, biodevices and other MEMS devices.     

1,4-二咔唑基苯微米结构的可控制备及光波导性质

采用液相组装法通过改变组装条件制备了高结晶性、宽度为2μm、长度为10～40μm的1,4-二咔唑基苯一维微米线(BeCzMW). X射线衍射和选区电子衍射结果表明,BeCz分子沿着晶体[100]方向生长.通过扫描近场光学显微镜进一步发现,BeCzMW被紫外激光激发后产生的荧光被限域在一维结构中,并沿着一维方向进行传导.BeCzMW在420 nm处的光学损耗系数R=0. 0628 dB/μm,表明BeCzMW具有良好的光波导性能.     

Zinalco and Zircaloy-4 nuclear characterization

Zinalco and Zircaloy-4 samples were used in order to measure the gamma-ray attenuation coefficients for three different gamma-ray energies. Using the neutron activation analysis technique, the elemental composition of Zinalco and Zircaloy-4 was measured.     

Egyptian and foreign cigarettes

Neutron activation analysis has been employed to determine the concentration of 27 elements in an Egyptian cigarette filter before and after smoking. The filter of three foreign cigarette brands are also analyzed and compared to the Egyptian brand. The elements determined are Al, As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Mg, Mn, Na, Ni, Rb, Sb, Sc, Se, Sr, Th, Ti, V and Zn. It is observed that the concentration of the measured elements in the Egyptian brand are within the concentration range of foreign brands, and that the concentration of As, Br, Cl, K, Na and Se in the filters are increased after smoking regardless the brand examined.     

Coordination compounds of hydrazine derivatives with transition metals,Part 17. Nickel (II) and cobalt(II) chelates with pyridine-2-aldehyde semi- and thiosemicarbazone

Summary The chelation abilities of both pyridine-2-aldehyde semicarbazone (Pysc) and thiosemicarbazone (Pytsc) towards Ni^II and Co^II salts have been investigated. A series of pentacoordinate monoligand chelates: Ni(Pysc)X₂, Ni(Pytsc)X₂ and Co(Pysc)X₂ and octahedral bis ligand chelates Ni(Pysc)₂X · NO₃ Ni(Pytsc)₂X₂ and Co(Pysc)₂X₂ have been isolated and identified. In these chelates, both Pysc and Pytsc act as neutral tridentate ligands. The deprotonated form of Pyts, which arises through enolization, is identified in N^II chelates and is of the type Ni(PytscH)₂ and Ni(PytscH)X. Spectral and magnetic measurements are presented and attention is drawn to the effect of temperature on the solution spectra of some of the chelates.     

Decompositions of universal algebras by idempotent algebras

An algebra with units is an algebra in which every subalgebra contains a singleton subalgebra. A one-unit-algebra is an algebra in which every subalgebra contains exactly one singleton subalgebra. IfU,V are subclasses of a classK of algebras,U _K V is the class of all K on which there is a congruence such that /V and every -class that is a subalgebra of belonging toK belongs also toU, e.g., ifK is the class of all semigroups,V is the class of all bands andU is the class of all groups,U _K V is the class of all bands of groups. We studyU _K V andU _K U whereU is a class of one-unit-K-algebras andV is a class of idempotentK-algebras. IfK is a class of algebras of type closed under subalgebras and homomorphisms,U is the class of all one-unit-K-algebras andV is the class of all idempotentK-algebras, thenU _K V is the class of allK-algebras that are -reducts of , e-algebras satisfying e(x) is a singleton subalgebra for everyx A belonging to the -subalgebra of generated byx and e(f(– x₁, x₂,..., x_n))=e(fe(x₁), e(x₂),..., e(x_n)) for every n-ary operationf of type . IfK is a variety of algebras with units and of finite type,U andV are finitely based (relative toK) subquasivarieties ofK, thenU _K V is finitely based relative toK. IfK is the variety of all commutative groupoids with an additional unary operatione satisfying e(e(x))=e(x)=e(x)· e(x), e(x · y)=e(x)· e(y),U andV are the subvarities ofK defined by e(x)=e(y) andx=e(x) respectively, thenU _K U is neither a variety nor finitely based. Some applications to semigroups and quasigroups are considered.Presented by G. Grätzer.