Investigation of Composition of Endometallofullerene Extracts

Abstract

Gases evolved upon heating endometallofullerene (EMF) extracts with La or Y have been investigated. It has been shown that solvent molecules used to release EMF are observed in extracts up to high temperatures. It has been found that in the dimethylformamide (DMF) extract the EMF molecules are present mainly as the [EMF]^? anions, which were observed in electrospray mass spectra. The treatment of such extracts with iodine results in the anion reduction to neutral molecules.     

Aggregation of Endometallofullerene Y@C82 in Polar Solvents

Abstract

Having studied the optical absorption, fluorescence spectra and dynamic light scattering (DLS) of solutions of Y‐EMF in polar solvents, we demonstrated for the first time that the endohedral metallofullerenes (EMF) forms nanoparticles, the mean size of which ranges up to 100 nm.     

Experimental Evidence in Support of the Formation of Anionic Endohedral Metallofullerenes During Their Extraction with N,N-Dimethylformamide

In an effort to test possibility of the formation of anions of endohedral metallofullerenes (EMF, M@C_2n) during their extraction from EMF containing soot we study different EMF extracts applying electrospray ionization mass spectrometry (ESI-MS). The ESI-MS (negative mode) analysis of Y@C_2n and La@C_2n extracted by either N,N-dimethylformamide (DMF) or CS₂ reveals that under DMF extraction diamagnetic monoanionic EMF can be successfully generated that was also substantiated by study of interaction between DMF extract of Y@C_2n and bis(triphenylphosphoranylidene)ammonium chloride.     

Electromagnetic filteration of primary Fe-rich phases from AI-Si alloy melt

Electromagnetic filtration primary Fe-rich phases (complex compound of AlFeSiMn) from Al-Si alloy melt containing 1.2 wt pet Fe have been studied by theoretical analysis and on a self-designed electromagnetic filtration equipment. The principle of the electromagnetic filtration is that the EMF (electromagnetic force) scarcely acts on the primary Fe-rich phases having low electric conductivity, which are then moved in the direction opposite to that of the EMF. Experimental results show that the primary Fe-rich phases are separated from AI-Si alloy melt and are collected in the filter while the melt is in horizontal flow. The removal efficiency of the primary iron-phases (eta) calculated is less as the greatest flow velocity of the melt (u(M)) and the height of the filter (2h) are larger, while it becomes larger as EMF, operating distance of electromagnetic force (x) and particle size (d(p)) become larger. It has been confirmed that the primary iron-phases larger than 20 mum can be removed efficiently by theoretical analysis and experiments. This new technique is high efficient and available for continuously flowing melts as compared with natural settling and filtration methods, which offer a Possibility for recycling high quality aluminum alloys.     

Spin‐Transparency of the Fullerene Shell of Endometallofullerene La@C82

Abstract

For La@C₈₂ embedded into the polycarbonate film, an intensive ¹H‐electron‐nuclear double resonance (ENDOR) has been revealed. Since La‐EMF does not contain hydrogen atoms, it evidences for the electron spin density on the matrix protons. Furthermore, for the solutions of La‐EMF in hexamethylphosphoramide (HMPA), the paramagnetic shift of the ³¹P NMR signal of bulk solvent molecules has been revealed. These findings testify the partial localization of unpaired electron outside the fullerene cage. The “transparency” of the fullerene shell to the electron spin density may serve the important factor in designing the fullerene‐based materials.     

Aggregation of Endometallofullerene Y@C82 in Polar Solvents

Having studied the optical absorption, fluorescence spectra and dynamic light scattering (DLS) of solutions of Y-EMF in polar solvents, we demonstrated for the first time that the endohedral metallofullerenes (EMF) forms nanoparticles, the mean size of which ranges up to 100 nm.     

Study on the biostability of chlorophyll a entrapped in silica gel nanomatrix

Chlorophyll a has been extracted mainly from fresh leaves and subsequently entrapped in nano porous silica gel matrix through the sol gel route under varying pH conditions. UV–VIS spectroscopy fluorescence and FTIR spectroscopy have been carried out to study the structure and stability of entrapped chlorophyll as a function of sol pH and time after entrapment. It is observed that chlorophyll molecules remain structurally unaltered on entrapment of sol pH of 6.8. Increasing acidic condition indicates gradual changes of chlorophyll extracts e.g., removal of Mg. However once entrapped chlorophyll molecules remain stable irrespective of the sol pH condition. Chlorophyll molecules entrapped in silica gel matrix also appear resistant to degradation by water. It has been proposed that pyroll type ring of the porphyrene moiety forms a weak bond with the unfilled d orbital of the matrix silicon. This imparts stabilization of chlorophyll within silica gel matrix, without any external stabilization agent.     

Electromagnetic Filtration of Primary Fe-Rich Phases from Al-Si Alloy Melt

Electromagnetic filtration of primary Fe-rich phases(complex compound of AIFeSiMn)from Al-Si alloy melt containing 1.2 wt pct Fe have been studied by theoretical analysis and on a selfdesigned electromagnetic filtration equipment. The principle of the electromagnetic filtration is that the EMF(electromagnetic force)scarcely acts on the primary Fe-rich phases having low electric conductivity, which are then moved in the direction opposite to that of the EMF.Experimental results show that the primary Fe-rich phases are separated from Al-Si alloy melt and are collected in the filter while the melt is in horizontal flow.The removal efficiency of the primary iron-phases(η)calculated is less as the greatest flow velocity of the melt(uM)and the height of the filter (2h) are larger,while it becomes larger as EMF, operating distance of electromagnetic force (x) and particle size (dp) become larger. lt has been confirmed that the primary iron-phases larger than 20 μm can be removed efficiently by theoretical analysis and experiments. This new technique is high efficient and available for continuously flowing melts as compared with natural settling and filtration methods, which offer a possibility for recycling high quality aluminum alloys.     

板材电磁成形技术研究进展

电磁成形是一种典型的高速率成形技术,能显著提高材料的成形性能,并已经成功应用于金属板材成形领域,获得了很好的成形效果.为了能够继续扩大电磁成形技术在板材成形方面的应用,对目前板材电磁成形技术研究进展进行了综述.首先介绍了电磁成形工艺的原理与主要特点;分析了目前电磁成形技术、电磁辅助冲压成形技术在金属板材成形方面的研究进展;提出了电磁成形技术在应用研究方面存在的主要问题,并展望了该技术的发展趋势;最后,分别从成形材料和成形工艺两个方面分析了后续研究的突破点以实现扩大该技术应用的目的.     

Potentiometric response characteristics of polycation-sensitive membrane electrodes toward poly(amidoamine) and poly(propylenimine) dendrimers

The potentiometric response characteristics of polycation-sensitive membrane electrodes toward two classes of polycationic dendrimers are examined. Using appropriately formulated polymer membrane electrodes composed of a dinonylnaphthalenesulfonate (DNNS) salt in a plasticized polyurethane matrix, it is shown that poly(amidoamine) (PAMAM) and poly(propylenimine) (PPI) dendrimers are readily detected at submicrogram per milliliter levels via a nonequilibrium response mechanism. The relationship between the total EMF response (at equilibrium) and the specific dendrimer structure is also examined. For both the PAMAM and PPI species, it is shown that the total EMF response does not change significantly with dendrimer generation number; however, the nonequilibrium analytically useful response curves are shifted to higher mass concentrations as the generation number is increased. The relative contributions of the terminal primary amines and the interior tertiary amines of the dendrimers to the observed EMF response are investigated by synthesis of various dendrimer derivatives (acetylated, quaternized, etc.). By comparing the total EMF responses for these derivatives as a function of sample pH, it is demonstrated that the lipophilic cation exchanger (DNNS) within the membrane phase can likely interact electrostatically with both protonated forms of the terminal primary amines and interior tertiary amines of the dendrimer structures. The practical application of the nonequilibrium potentiometric detection of dendrimers for monitoring their interaction with DNA is also demonstrated.     

不同热处理状态铝合金在电磁成形条件下的成形性研究

目的 研究不同热处理状态下多种铝合金在准静态拉伸和电磁单向拉伸条件下的成形性能,并探究其中机理.方法 选择不同牌号(1060,3003,5052)和不同热处理状态(加工硬化态和完全退火态)的铝合金材料,获得材料在准静态和电磁成形条件下材料的成形性能,并通过扫描电镜(SEM)和透射电镜(TEM)对1060铝合金试样进行显微断口和微观组织分析.采用数值仿真方法,获取板料和线圈的最佳相对位置.结果 与退火态材料相比,在电磁成形条件下加工硬化态材料的成形性能提高得更多,特别是在1060铝合金中,退火态试样准静态拉伸的伸长率和动态拉伸的伸长率几乎一致,而H24态试样的动态拉伸伸长率(20.2％)为准静态拉伸(5.1％)的3.96倍.扫描断口发现电磁成形断裂面更窄,韧窝大小更均匀.1060-O试样电磁成形后,晶粒内部位错密度低,微观结构主要为亚晶.1060-H24试样电磁成形后的组织中位错密度较高,出现位错胞.结论 加工硬化态材料中存在的初始缺陷有利于电磁成形过程中位错的产生和交滑移的发生,从而提高合金成形性.     

The Effects of Electric and Exchange Magnetic Fields on Spin Energy Dispersion,Electronic Heat Capacity and Magnetic Susceptibility of Monolayer Silicene

The Kane-Mele model and Green’s function technique help us to describe and survey the influences of electric and exchange magnetic fields (EF and EMF) on the dynamics of Dirac fermions in the monolayer silicene by studying the energy dispersion (ED), electronic heat capacity (EHC) and Pauli magnetic susceptibility (MS). Spin band gaps show three phases including topological insulator (TI), valley-spin polarized metal (VSPM) and band insulator (BI) in the presence of external EF. The maximum value for EHC and MS have been observed in the VSPM phase. Also, ED evolution with EMF shows that the Fermi level decreases. Interestingly, two critical temperatures have been found in the VSPM regime of 0.5 and 2 in terms of spin-orbit coupling (SOC) strength in the EHC and MS curves, respectively. In addition, remarkable point in the VSPM regime is the observed phase transition from antiferromagnetic to paramagnetic in MS curves. Competition between thermal and quantum effects is the main reason of these critical points which these findings can control the thermal properties of silicene-based devices.     

Determination of ginsenosides in plant extracts from Panax ginseng and Panax quinquefolius L. by LC/MS/MS

An HPLC/MS/MS method has been developed for the characterization and quantification of ginsenosides contained in extracts of the root of Panax ginseng (Korean ginsengs) and Panax quinquefolius L. (American ginsengs). The [M + H]+ and [M + Na]+ ions were observed for ginsenoside standards (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1) and four different ginseng extracts. The glycosidic linkages, the core, and the attached sugar(s) of the ginsenosides can be determined from the collision-induced dissociation spectra from the protonated molecules. The relative distribution of these ginsenosides in each extract of American or Korean ginseng was established.     

Designing printed circuit stators for brushless permanent magnet motors

Progress in a number of areas of technology has made printed circuit motors a serious contender for many applications. Modern cost effective neodymium magnets have allowed compact motor designs. Multi-layer circuit board production techniques have made the production of printed circuit coils cheaper and easier. However, in spite of the growing importance of printed circuit brushless motors, there is a lack of analytical tools to assist with their design. Geometrical analysis has been used to allow the plotting of printed circuit tracks to be carried out more systematically. The track plotting procedures have been linked with the finite element method to predict rotational electromotive force (EMF) waveforms. Six prototype motors were built and they were used to experimentally validate the method of predicting EMF waveforms. A general design algorithm is presented based on the suggested track plotting procedure and the EMF prediction technique.     

Tuning luminescence intensity of RHO6G dye using silver nanoparticles

The photoluminescence (PL) from rhodamine (RHO6G) dye dispersed in ethanol has been studied in the presence of different amounts of citrate stabilized silver nanoparticles of size, ∼10 nm. Enhancement as well as quenching of luminescence intensity has been observed and it was found that luminescence intensity can be tuned by adding various amounts of silver nanoparticles to the RHO6G dye dispersion. The luminescence spectra of dye consist of two peaks at 440 nm and 550 nm. Peak at 440 nm shows an enhancement in intensity at all the concentrations of added silver nanoparticles with the maximum intensity for dye with 0.25 ml silver nanoparticles (82% enhancement in the luminescence intensity). PL intensity of intense peak at 550 nm of dye molecules was found to be quenched in presence of silver nanoparticles and maximum quenching was found to be 41% for the dye with 1 ml silver nanoparticles. However, for lowest concentration of silver nanoparticles viz. (0.01 ml), enhancement in intensity was observed (13% enhancement than the dye molecules). The quenching as well as enhancement in the intensity can be understood by considering the possibility of three different phenomena. It has been reported earlier that when metal nanoparticles are in close proximity to the fluorophores, quenching of luminescence occurs, whereas when metal nanoparticles are located at certain distance, enhancement in luminescence is observed. This effect has been explained by coupling of surface plasmon resonance from metal nanoparticles with fluorophore, resulting in the increase of excitation and emission rate of the fluorophore in the localized electromagnetic field. The quenching and enhancement of luminescence intensity of the dye molecules can also be explained as the transfer of electrons from dye to the silver nanoparticles and to an extent it can be attributed to the aggregation of dye molecules upon addition of silver nanoparticles.     

Microstructure and electrical property of TiNx films deposited by DC reactive magnetron sputtering superimposed electromagnetic field system

TiNx films were successfully deposited by DC reactive magnetron sputtering superimposed EMF system without substrate heating. In case of DCMS 400 W+ EMF 25 W, electrical property, reflectance and crystallinity of the TiN films were clearly improved by the enhancement of nitrification. The lowest sheet resistance of 2.9 Ω/? (resistivity 5.8 x 10(-5) Ωcm) was observed for the film deposited at F(N)2: 16%. Mixture phases of the (111) plane and (200) plane showed lower resistivity than only (200) single phase. Therefore it is confirmed that introduction of EMF system is promising technology to deposit TiN film.     

N-step linear phase-shifting algorithms with optimum signal to noise phase demodulation

The wave side of wave–photon duality, describing light as an electromagnetic field (EMF), is used in this article. The EMF of spontaneous light emission (SE) of a laser-excited atom is calculated from first principles for the first time. This calculation is done using the simple method of atomic quantum electrodynamics. The EMF of SE is also calculated for three types of polyatomic light sources excited by a laser. It is shown that light radiated by such sources can be coherent, which explains recent experiments on SE of laser-excited atoms. Small sources of SE can be superradiant, which also conforms to experiment. Thus, SE is shown not to be a random event itself. Random properties of natural light are simply explained as a result of thermal excitation randomness without additional hypotheses. The EMF of SE is described by simple complex functions, but not real ones.     

Far-infrared radiation absorption cross section of clusterized water vapor

A molecular dynamics simulation of an ensemble of water molecules has been performed using a flexible polarizable model. Far-infrared (FIR) radiation absorption cross sections of water vapor with various degrees of clusterization have been calculated in the dipole oscillator approximation. It is shown that the radiation absorption by libration vibrational modes is already observed for the clusters involving about ten molecules and shifts the absorption spectrum toward the maximum of the thermal radiation spectrum of the Earth.     

The characteristic of millivolt EMF standard cells

A CdSO₄ and Cd-amalgam based cell with an EMF of approximately 1.015 mV at 20°C is considered. Research showing that the cell is highly stable and reversible is reported. The EMF-temperature hysteresis is very small, and the reversibility is very good during charging and discharging. The cell can be used as a practical 1-mV reference standard for EMF. A millivolt cell has been constructed as a 1-mV secondary standard within ±5 mK. The characteristics and construction of the standard cell are reported     

FeNi29Co18MnSi合金材料热电特性的影响研究

主要研究了FeNi29CO18MnSi合金材料的热电特性,分析了Ni-Co合金、Ni-Fe合金的热电性能,研究了FeNi29Co18MnSi合金中Mn、Si含量及冷形变对合金热电势的影响.研究表明,随着微量添加元素Mn、Si含量的增加,合金单极对铂(Pt)的热电势绝对值减小,且合金冷形变对热电势具有较大的调整作用.