An Investigation into the Isolation Performance of Mono-and Bi-stable Systems

Motivated by the need for improving the isolation performance, many research studies have been performed on isolators with nonlinear characteristics. Based on the shape of their phase portrait, such devices can be configured as either a mono-or bi-stable isolator. This paper focuses on investigating the relative performance of these two classes under the same excitations. Force transmissibility is used to measure the isolation performance, which is defined in terms of the RMS of the ratio of the transmitted force to the excitation force. When the system is subjected to harmonic excitation, it is found that the maximum reduction of the force transmissibility in the isolation range using Quasi-Zero stiffness is achieved. When the system is subjected to random excitation, it has the same effect of Quasi-Zero stiffness. Further, optimum damping can be changed with stiffness and has minimum value.

Synthesis and Structural Characterization of Mono-and Di-nuclear Zinc(Ⅱ) Coordination Compounds of Triphenylphosphoniopropionate

Two novel coordination compounds of Zn(Ⅱ) with Ph_3P+(CH_2)_2CO-_2(L), namely, [ZnL_4(H_2O)_2]·(ClO_4)_2·2H_2O(compound 1) and [Zn_2Cl_4(μ-L-O,O′)_2](compound 2), have been prepared. The single crystal X-ray structure analysis of these compounds indicates that in compound 1 the Zn(Ⅱ) atom is coordinated by four monodentate carboxylato groups on the equatorial plane and two aqua ligands occupy the axial coordination positions. The pendant oxygen atoms form strong hydrogen bonds with the aqua molecules which results in the stability of this structure. In compound 2, two Zn(Ⅱ) atoms are bridged by a pair of carboxylato groups, showing a skew-bridge mode, and thus enabling a long Zn(Ⅱ)…Zn(Ⅱ) separation. As we know, it is a dinuclear coordination compound with the longest Zn…Zn separation.

A Study on the Inclusion of α-Cyclodextrin with Mono-and 1,4-Disubstituted Benzenes by Neural Networks

The association constant (Ka) values were calculated by the function-strengthen ing neural networks (FNN) for the inclusion complexation of α-CD with mono- and 1,4-disubstituted benzenes. The lnKa predicted by FNN from Rm, π and σ constants of substituents are in great agreement with the experimental data.

Inhibition of DNA restrictive endonucleases by aqueous nanoparticle suspension of methanophosphonate fullerene derivatives and its mechanisms

Aqueous nanoparticle suspension of fullerene and its derivatives are currently attracting much attention. To determine the effects of aqueous nanoparticle suspension of a mono-methanophosphonate fullerene and bis-methanophosphonate fullerene (denoted as n-MMPF and n-BMPF, respectively) on the activities of DNA restrictive endonucleases, plasmid pEGFP-N1 was cleaved at a single but differently restrictive site by EcoR I, BamH I, and isozymes Cfr9 I and Xma I, respectively. Both n-MMPF and n-BMPF inhibited the activity of EcoR I, while n-BMPF exhibited stronger inhibition than n-MMPF. Addition of n-BMPF into reaction mixtures inhibited the activities of all the four enzymes, and IC50 values for EcoR I, BamH I, Cfr9 I and Xma I were 4.3, >30, 11.7 and 8.3 μmol/L, respectively. When EcoR I was completely inhibited by n-BMPF, addition of excess amounts of pEGFP-N1 could not produce the product linear plasmid; however, increase of EcoR I amounts antagonized EcoR I inhibition of n-BMPF. Two scavengers of reactive oxygen species (ROS), mannitol and sodium azide at the concentrations of 2-10 mmol/L, did not reverse inhibition of n-BMPF, implying that this inhibition probably is not correlated to ROS. These results suggested that aqueous nano-fullerenes might act as inhibitors of DNA restrictive endonucleases.

Parametrization of Mean Radiative Properties of Optically Thin Steady-State Plasmas and Applications

Plasma radiative properties play a pivotal role both in nuclear fusion and astrophysics.They are essential to analyze and explain experiments or observations and also in radiative-hydrodynamics simulations.Their computation requires the generation of large atomic databases and the calculation,by solving a set of rate equations,of a huge number of atomic level populations in wide ranges of plasma conditions.These facts make that,for example,radiative-hydrodynamics in-line simulations be almost infeasible.This has lead to develop analytical expressions based on the parametrization of radiative properties.However,most of them are accurate only for coronal or local thermodynamic equilibrium.In this work we present a code for the parametrization of plasma radiative properties of mono-component plasmas,in terms of plasma density and temperature,such as radiative power loss,the Planck and Rosseland mean opacities and the average ionization,which is valid for steady-state optically thin plasmas in wide ranges of plasma densities and temperatures.Furthermore,we also present some applications of this parametrization such as the analysis of the optical depth and radiative character of plasmas,the use to perform diagnostics of the electron temperature,the determination of mean radiative properties for multicomponent plasmas and the analysis of radiative cooling instabilities in some kind of experiments on high-energy density laboratory astrophysics.Finally,to ease the use of the code for the parametrization,this one has been integrated in a user interface and brief comments about it are presented.

Late-stage diversification by rutheniumelectro-catalyzed C–H mono- and di-acyloxylation

A ruthenium-catalyzed electrochemical dehydrogenative C(sp^(2))H acyloxylation of aniline derivatives with carboxylic acids has been developed.Electric current is used to recycle the active ruthenium-based catalyst and promote H_(2) evolution.This method significantly expands the scope and enhances the selectivity of metal-electron catalyzed mono-and di-acyloxylations,which remain challenged.Our findings allowed mono-selectivity in broadly effective late-stage diversification of structurally complex drugs and natural product molecules,tolerating drugs,natural products and amino acids.The method and its underlying strategy are expected to have widespread uses in functional aniline synthesis and drug discovery process.