New diterpenoids from Calceolaria polifolia

Four new and seven known diterpenes have been isolated from the dichloromethane extract of the aerial parts of Calceolaria polifolia. The structures of the new compounds were established by spectroscopic evidence.     

几种乙酸铵离心法测定土壤阳离子交换量的方法探讨

乙酸铵离心交换法测定酸性和中性土壤阳离子交换量是经典方法,但此方法的蒸馏过程繁琐、时间长、效率低。本文引用纳氏试剂分光光度法测定土壤CEC值,并将结果与乙酸铵离心法常用的几种传统测定方法进行了实验对比和总结。通过对国家标准样品及实际土壤样品的CEC值测定,纳氏试剂比色法的精密度在2-4%之间,准确度与经典方法一致。与传统滴定法比较,取代了蒸馏的步骤,测定方法简单,干扰少,结果可靠,可操作性强。     

Recovering information in probabilistic quantum teleportation

Frontiers of Physics - Recently, the BESIII collaboration has reported numerous measurements of various D(s) meson semileptonic decays with significantly improved precision. Together with similar...     

Determination of reactions between free radicals and selected Chilean wines and transition metals by ESR and UV-vis technique

Four different types of Chilean wines (Cabernet Sauvignon, Merlot, Carmenere and Syrah) were selected and examined in their free radical scavenging capacities by electron spin resonance (ESR) and spectrophotometric methods. The free radical scavenging properties were evaluated against 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical, 2,6-di-tert-butyl-alpha-(3,5-di-tert-butyl-4-oxo-2,5-cyclohexadien-1-ylidene)-p-tolyloxy (Galvinoxyl) radical and hydroxyl radical (HO*). The possible effect on these scavenging properties of added transition metals to these wines was evaluated. Among the wines evaluated, Cabernet Sauvignon was the one with the highest activity against all radicals tested. The presence of added copper or iron to wines resulted in a reduced free radical scavenging capacity for all type of wines studied. The formation of redox inactive complexes between polyphenols of wine and transition metals is the possible cause of this reduction in antioxidant activity.     

Oil in Louisiana's estuarine environments: A development model

Coastal erosion, accelerated by sea level rise, and subsidence are major Louisiana issues. With current sea-level-rise projections, coupled with the state's eroding barrier islands and coastal wetlands, the region's estuarine environments are in jeopardy of being lost, redefined, or permanently altered. As the coast erodes, Louisiana is endangered of losing valuable wetland's habitat. In addition, if the barrier islands disappear, the region's wetland-oriented oil and gas wells and associated infrastructure will be at risk to open Gulf conditions. If this should occur, each well, pipeline, and storage battery represents a potential environmental catastrophe.     

Controlled Fabrication of Cd-Bi Nanoparticles via Sonochemical Method

IntroductionMetal or alloy nanoparticles,because of their con-spicuous physicochemical properties,have been widelyapplied to various fields such as electronics,catalysis,magnetism,and corrosion-resistant materialsfields[1—4].It has been estimated that the particle sizeand the properties of nanoparticles depend strongly onthe specific method of fabrication and the applied ex-periment conditions,which makes the controlled syn-thesis of nanomaterials become an increasingly activeand important ar…     

素理想完全分裂的一个判别法则

本文给出了数域K内一个素理想在K的有限次正规扩域L内完全分裂的一个判别法则。     

Reactivity of a two heteroatom stabilized anionic chromium (0) carbene complex towards a mono- and a disubstituted alkyne: New synthesis of γ-aminobutenolides and formation of a novel oligomer chromium (0) complex

The reaction of the chromium anionic carbene complex 1 towards diphenylacetylene and phenylacetylene is reported. In the former case the synthesis of γ-functionalized butenolides results after demetallation of the chromium complex 2 and the latter leads to the formation of a novel oligomer chromium complex 5. These complexes were characterized by mass spectrometry, IR and ¹H and ¹³C NMR spectroscopies and their structures were confirmed by single-crystal X-ray analysis.