“Could charm (& τ ) transitions be the ‘poor princess’ providing a deeper understanding of fundamental dynamics ?” or: “Finding novel forces”

We know that our Universe is composed of only ～4.5% “known” matter; therefore, our understanding is incomplete. This can be seen directly in the case of neutrino oscillations (without even considering potential other universes). Charm quarks have had considerable impact on our understanding of known matter, and quantum chromodynamics (QCD) is the only local quantum field theory to describe strong forces. It is possible to learn novel lessons concerning strong dynamics by measuring rates around the thresholds of [QˉQ] states with Q = b, c. Furthermore, these states provide us with gateways towards new dynamics (ND), where we must transition from “accuracy” to “precision” eras. Finally, we can make connections with τ transitions and, perhaps, with dark matter. Charm dynamics acts as a bridge between the worlds of light- and heavy-flavor hadrons (namely, beauty hadrons), and finding regional asymmetries in many-body final states may prove to be a “game changer”. There are several different approaches to achieving these goals: for example, experiments such as the Super Tau-Charm Factory, Super Beauty Factory, and the Super Z⁰ Factory act as gatekeepers – and deeper thinking regarding symmetries.     

Synthesis, characterization and DFT calculations of new ethynyl-bridged C60 derivatives

A new series of soluble C₆₀ derivatives for organic electronic application has been synthesized by ethynylation reaction using different electron-donating and electron-withdrawing groups of varying length.     

Benchmarking of maintenance performance: a case study in two manufacturers of furniture

When profit margins of a plant are decreasing, the need forreliable and efficient maintenance policy becomes more important.Measuring maintenance performance is important for companiesto recognize whether their planned goals are achieved or not.Also, such measurements can be utilized for benchmarking, whichis one of the tools for never-ending improvement. But, theseobjectives cannot be achieved without well-documented data ofthe relevant variables. Better data coverage and quality isnecessary for following maintenance performance developmentand it would, in many cases, clarify the ambiguity concerningthe main problem in the context, namely that neither the productionnor maintenance department can show what effect maintenancehas on profitability. A more effective maintenance policy indirectly implies improvementsin product quality and manufacturing process effectiveness.Elongation of the production time, i.e. reducing the downtimedue to failures, planned replacements and repair, in additionto the improvement in the total maintenance activities, arealso some of the results that can be expected when an efficientmaintenance policy is used. Measuring and monitoring maintenanceperformance measures is required partly for detecting, and eventuallytreating as soon as possible, undesirable changes and partlyto make benchmarking with the best in the branch, which savesappreciable economic losses for companies. In this paper, a model for how to identify the measurable variables,which are needed to develop measures for monitoring maintenanceperformance behaviour systematically, is developed. Five maintenanceperformance measures are proposed and applied. An additionalmodel for systematically analysing the trend of maintenanceperformance measures, for an overall assessment of the company'ssituation, is presented. Two case studies in manufacturers offurniture are conducted to verify these models.     

Tan relations in one dimension

We derive exact relations that connect the universal C/k⁴-decay of the momentum distribution at large k with both thermodynamic properties and correlation functions of two-component Fermi gases in one dimension with contact interactions. The relations are analogous to those obtained by Tan in the three-dimensional case and are derived from an operator product expansion of the one- and two-particle density matrix. They extend earlier results by Olshanii and Dunjko (2003) [24] for the bosonic Lieb–Liniger gas. As an application, we calculate the pair distribution function at short distances and the dimensionless contact in the limit of infinite repulsion. The ground state energy approaches a universal constant in this limit, a behavior that also holds in the three-dimensional case. In both one and three dimensions, a Stoner instability to a saturated ferromagnet for repulsive fermions with zero range interactions is ruled out at any finite coupling.     

固相萃取-气相色谱/质谱联用法测定儿童手推车中3种有机磷酸酯阻燃剂

有机磷酸酯是一类重要的磷系阻燃剂,由于其具有类似持久性有机污染物(persistent organic pollutants, POPs)的性质,欧美等国家已纷纷设立相关法规限制其在儿童用品中的使用。目前国际和国内均未有儿童手推车中有机磷酸酯阻燃剂的检测标准。本文建立了儿童手推车中3种有机磷酸酯阻燃剂的超声萃取-弗罗里硅土固相萃取柱净化-气相色谱/质谱检测方法。该方法的加标回收率为89.5%~107.3%,检出限(3S/N)为0.01 mg/kg,定量限(10S/N)为0.1 mg/kg,能较好地排除基质干扰,适用于儿童手推车软垫材料中3种有机磷酸酯的定性和定量分析。37个样品的分析结果表明,磷酸三(2-氯丙基)酯(TCPP)的检出率为81.1%,含量范围为1.0~15312.8 mg/kg,依据欧盟玩具新指令2014/79/EU, TCPP超标(> 5 mg/kg)率为32.4%;其中2个样品中还检出了磷酸三(2-氯乙基)酯(TCEP)和磷酸三(1,3-二氯-2-丙基)酯(TDCP),含量范围为6.2~44.1 mg/kg,均已超标。可见,市场上的儿童手推车存在较高的有机磷酸酯阻燃剂暴露风险。     

One—and Two—photon Excited Fluorescence of Zinc（Ⅱ）,Cadmium（Ⅱ）Complexes Containing Phenothiazine Ligand

A new ligand,10-ethylphenothiazinyl-3-yl-methylene thiosemicarbazon(HL) and its complexes ML2 (M=Zn^2 ,Cd^2 ),which exhibit intensive two-photon excited (TPE) fluoresce at 800 nm laser pulses in femtosecond regime,were synthesized and characterized.The measured power dependence of the fluorescence signals provided direct evidence for TPE.All of them exhibited a large two-photon absorptive cross section and ,more importantly from the application point of view,high photochemical/photothermal stability.     

Calculation of the Mass of X（3872） by the Mandelstam Generalization of the Gell-Mann-Low Method

On the basis of assuming that the narrow state X（3872） is a molecule state consisting of D0 and D＊0, we apply the Mandelstam generalization of the Ge11-Mann-Low method to calculate the matrix element of quark current between the heavy meson states described by Bether-Salpeter wave function. In calculation of the matrix element of quark current the operator product expansion is used in order to include the nonperturbative contribution of the vacuum condensates. In this scheme we calculate the mass of X（3872）. We believe that this scheme is closer to QCD than the previous work.     

Upon the intrinsic optical properties of oligo(p-phenyleneethynylene)s (OPEs). Synthesis of OPE3 for experimental gas-phase absorption studies

A new oligo(p-phenyleneethynylene) (OPE3) was synthesized by step-wise Pd-catalyzed cross-coupling reactions. The molecule incorporates an amine functionality, which allows for transfer of the protonated molecule to the gas phase by electrospray ionization leaving the OPE entity neutral. This method has allowed for the first experimental gas-phase absorption spectrum of an OPE3 by action spectroscopy, employing an electrostatic ion storage ring in combination with a laser system. The studies reveal the effect of having a positive charge in proximity to the conjugated backbone of OPE3 in the absence of any interfering solvent molecules. In addition, ionization energies and electron affinities of OPE2-OPE17 were calculated at the density functional theory (DFT) level.     

One-and Two-photon Excited Fluorescence of Zinc(II),Cadmium(II)Complexes Containing Phenothiazine Ligand

In fluorescence imaging, two-photon excitation (TPE) has developed as an important alternative to traditional one-photon excitation (OPE) in fluorescence microscopy and spectroscopy1,2. The intrinsic advantages of the two-photon excitation include reduced background fluorescence from fluorophores outside the focal volume, decreased photobleaching, inherent optical sectioning capability, and lower photodamage of sensitive biological sample3. But, all the reported materials, which exhibit a …     

Effects of substituents on molecular devices

The current–voltage characteristics of small aliphatic chains of alkanes, alkenes, alkynes, and oligophenylene‐ethylenes, with and without substituents and terminated in sulfur attached nanosized gold electrodes are determined using ab initio procedures for discrete and extended systems in a density functional theory‐Green function's approach where most of the chemistry is considered. It is found that the current–voltage characteristics of small molecules can be tailored by the addition of substituents. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008