bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Crystal Structure and Magnetic Property of Diiron Complex [Fe(phen)3][Fe2OCl6]·2CH3CN
Authors: Yan Bing , Chen Zhi‐Da , Wang Shi‐Xi 
Published: May 2015

AbstractA new diiron complex has been synthesized and characterized by X‐ray single crystal structural analysis: [FeII(phen)3][FeIII2OCl6]·2CH3CN. The complex crystallizes in the monoclinic system, space group C2/c, with lattice parameters a = 21.162(4) Å, b = 15.168(3) Å, c = 14.812(3) Å, β= 112.71 (3)°, V = 4385.8(15) Å3, Dx = 1.543 Mg/m3, Z = 4. The corresponding variable temperature susceptibility measurement shows that there exists an antiferromagnetic interaction in the complex.
Structure Identification of Aporphine Alkaloids by On‐Line Coupling of HPLC‐NMR with Loop Storage
Authors: Tseng Li‐Hong , Braumann Ulrich , Godejohann Markus , Lee Shoei‐Sheng , Albert Klaus 
Published: May 2015

AbstractThe potential of coupling HPLC separation methodology to on‐line high resolution nuclear magnetic resonance (NMR) spectroscopy has been demonstrated with a mixture of nine aporphine alkaloids. A loop storage procedure after separation has facilitated the identification of closely eluted peaks (α = k2/k1 = 1.01 and Δv = 0.37 min = 367 μL). These were collected off‐line and identified by a 1D 1H NMR spectrum. For this purpose an automated procedure has been implemented which includes the use of shaped pulses, multiple solvents suppression and 13C satellite suppression of acetonitrile.
Vapor‐Phase Aldolization of n‐Butyraldehyde to 2‐Ethyl‐2‐Hexenal over Solid‐Base Catalysts
Authors: Zhu Wei‐De , Ko An‐Nan 
Published: May 2015

AbstractVapor‐phase aldol condensation of n‐butyraldehyde to 2‐ethyl‐2‐hexenal was studied at 1 atm and 150∼ 300°C in a fixed‐bed, integral‐flow reactor by using NaX, KX, γ‐Al2O3 and Na/NaOH/γ‐Al2CO3 catalysts. Ion exchange of NaX zeolite with potassium acetate solution results in a decrease of crystallinity and apparent lowering of surface area, whereas the basic strength is enhanced. Treatment of γ‐Al2O3 with NaOH and Na causes a large decrease of the surface area but strong enhancement of the catalyst basicity. The catalytic activity on the basis of unit surface area is in the order Na/NaOH/γ‐Al2O3 < KXU < KXW < NaX >γ‐Al2O3, in accordance with the relative catalyst basic strength. The molar ratio of trimeric to dimeric products increases with increasing the reaction temperature and the catalyst basic strength except for Na/NaOH/γ‐Al2O3. Very high selectivity of 2‐ethyl‐2‐hexenal (>98.5%) was observed for reactions over NaX zeolite at 150°C. Based on the FT‐IR and the catalytic results, the reaction paths are proposed as follows: self‐aldol condensation of n‐butyraldehyde, followed by dehydration produces 2‐ethyl‐2‐hexenal, which then reacts with n‐butyraldehyde and successively dehydrates to 2,4‐diethyl‐2,4‐octadienal and 1,3,5‐triethylbenzene. For the reaction over NaX, the calculated Arrhenius frequency factor and activation energy are 314 mol/g·h and 32.6 kJ/mol, respectively.
Envirocats, as Novel Solid‐Supported Catalysts for Friedel‐Crafts Acylation
Authors: Bandgar Babasaheb P. , Kasture Suhas P. 
Published: May 2015

AbstractThe Friedel‐Crafts acylation reactions of substituted benzenes with acid chloride or anhydrides proceeded smoothly in the presence of a catalytic amount of novel solid‐supported reagents such as EPZG, EPZ10, EPIC and EPZE. These catalysts are reusable and environmentally friendly.
Efficient Synthesis of 1,2,3,4,6‐Penta‐O‐acetyl‐L‐idopyranose
Authors: Hung Shang‐Cheng , Chen Chien‐Sheng 
Published: May 2015

AbstractAn efficient synthesis of 1,2,3,4,6‐penta‐O‐acetyl‐L‐idopyranose 2 from 3,5‐O‐benzylidene‐1,2‐O‐isopropylidene‐α‐D‐glucofuranose in five steps in 45% overall yield via hydroboration of enol ether, hydrolysis of L‐idofuranosyl sugar and acetolysis of 1,6‐anhydro‐β‐L‐idopyranose as key steps is described here.
Sesquiterpenes from Ligularia Fischeri
Authors: Wang Wen‐Shu , Zhu Qi‐Xiu , Gao Kun , Jia Zhong‐Jian 
Published: May 2015

AbstractPhytochemical investigation of the whole plant of Ligularia fischeri afforded two new sesquiterpenes 11‐hydroxy‐eremophil 1(10)‐en‐2,9‐dione (1); and 1β,11‐dihydroxy‐eremophil‐9‐ene (2); four known compounds (‐)‐4β,7α‐aromadendranediol (3); 1β,6α‐dihydroxyeudesm‐4(15)‐ene (4); Teucdiol A (5); Teucdiol B (6). The new compound structures were elucidated by spectroscopic methods including 2D‐NMR techniques.
An Efficient Synthetic Method and Single Crystal Structure of a 2:3 Adduct of Cyclohexyl Isocyanide and Dimethyl Acetylenedicarboxylate
Authors: Cheng Fong‐Yu , Sung Kuangsen , Lee Gene‐Hsiang , Wang Yu 
Published: May 2015

AbstractAn efficient synthetic method and single crystal structure of a 2:3 adduct of cyclohexyl isocyanide and dimethyl acetylenedicarboxylate are described.
Macrocyclic Polyether Phase Transfer Catalysts for Free Radical Polymerization of Acrolein
Authors: Hsu Hui‐Ping , Shih Jeng‐Shong 
Published: May 2015

AbstractMacrocyclic polyethers, e.g., crown ethers and cryptands, were prepared and employed as phase transfer catalysts for free radical polymerization of acrolein, a vinyl monomer, with persulfates (S2O82–) as initiators. The catalytic abilities of various macrocyclic polyethers as catalysts for the free radical polymerization of acrolein were found to be in the order: benzo‐15‐crown‐5 > dibenzo‐18‐crown‐6 > 12‐crown‐4 > 15‐crown‐5 > 18‐crown‐6 > cryptand‐22 with sodium persulfate (Na2S2O8) as initiator. Sodium persulfate proved to be a better initiator than ammonium persulfate or potassium persulfate with benzo‐15‐crown‐5 as a catalyst. Effects of solvents and temperature on the catalytic polymerization were also investigated. The polymerization rates in various solvents were in the order: dioxane > benzene > acetonitrile > acetone > dichloromethane > hexane > water. Comparison between bulk polymerization and solution polymerization was also made. Higher polymerization rate was observed at higher temperature. The molecular weights of polyacrolein and the conversion of monomer in reaction period were determined with gel permeation chromatography and ultra‐violet spectrophotometry, respectively. Concentration effects of crown ether and initiator were also investigated and discussed.
Colorimetric Determination of Seleniumin Various Environmental Samples
Authors: Chatterjee Sukumar , Pillai Ajai Kumar , Gupta Vinay Kumar 
Published: May 2015

AbstractA new reagent system using rhodamine‐B dye for the determination of selenium is described. The method is based on the reaction of selenium with acidified potassium iodide to liberate iodine. The liberated iodine bleaches the pink colour rhodamine‐B, which is measured at 555 nm. Beer's law is obeyed over the concentration range of 1–10 μg of selenium final solution volume of 25 mL (0.04–0.4 ppm) and the apparent molar absorptivity and Sandell's sensitivity was found to be 1.96× 105 l mol−1 cm−1 and 0.0004 μg cm−2, respectively. The method is simple, sensitive, and selective and is satisfactorily applied to micro‐level determination of selenium in various environmental and cosmetic samples.
Synthesis of Novel N‐Pyridylcantharidinimides by Using High Pressure
Authors: Lin Pen‐Yuan , Shi Sheng‐Jie , Lin Lun‐Huei , Chen Hsue‐Fen , Hsu Feng‐Lin 
Published: May 2015

AbstractThe recently described pressure reaction in the presence of trithylamine with subsequent thermal (200°C) cyclization provided 13N‐pyridylcantharidinimides 4a‐4m from aminopyridines and cantharidin in yields of 15–83%. 2‐Amino‐3,5‐dichloropyridine failed to yield 4n.
Spectroscopic Characterization of Some Tetradentate Schiff Bases and Their Complexes with Nickel, Copper and Zinc
Authors: Abd‐Elzaher Mokhles M. 
Published: May 2015

AbstractThree ligands have been formed by the 1:2 molar condensation of o‐phenylenediamine with salicyldhyde, 2‐hydroxy‐1‐naphthaldhyde or o‐hydroxyacetophenone. The potentially tetradentate ligands are N,N′‐bis(salicyldhyde)‐o‐phenylenediamine(SalophH2), N,N′‐bis(2‐hydroxy‐1‐naphthaldhyde)‐o‐phenylenediamine (NophH2) and N,N′‐bis(o‐hydroxyacetophenone)‐o‐phenylenediamine (AophH2), respectively. These ligands form complexes (1:1 molar ratio) with nickel, copper and zinc ions. The complexes have been characterized by IR, 1HNMR, MS, uv/vis spectra in addition to elemental analysis. The spectral data of the ligands and their complexes with nickel, copper and zinc are discussed in connection with the structural changes which occur due to complexation.
Infrared Chemical Sensor for Detection of Chlorinated Phenols in Aqueous Solutions Based on a ATR Waveguide Coated with Structural Designed Polymers
Authors: Yang Jyisy , Hon Hau‐Huang 
Published: May 2015

AbstractA combination of solid phase micro‐extraction (SPME) with attenuated total reflection (ATR) infrared spectrometry provides a fast and sensitive way to detect organic compounds in aqueous solutions. It is especially useful for detection of chlorinated organic compounds in environmental samples. Currently, analyses of organic compounds in aqueous solutions are limited to low‐polarity compounds by the SPME/ATR‐IR sensing method. This limitation was mainly caused by the low polarity nature of the SPME phase. To increase the capability of this method to detect more polar compounds and also to increase the sensitivity in detection of organic compounds, the principle of “like‐dissolve‐like” was used to design a specific SPME phase for a certain class of chlorinated compounds. To demonstrate this concept, chlorinated phenols were used as probe molecules and polyvinyl chloride was chemically modified with phenol, ‐naphthol and ‐naphthol to provide SPME phases with a similar chemical structure to chlorinated phenols. These polymers were used as SPME phases and their performance were compared with the commonly used SPME phases (i.e., polystyrene and polyisobutylene). Results indicated that naphthols attached to PVCs provided much lower compactness, which allows fast speed in absorption of phenols. Meanwhile, due to the structural similarity between naphthols attached to PVCs and phenols, much higher partition coefficients were found for these chemically modified PVCs than conventionally used polymers. To further increase the sensitivity for analysis of chlorinated phenols, the common influencing factors, such as pH values and salt effect were also investigated. Apparently, pH values of the solutions did not influence the structure of the modified PVCs significantly. In absorption of chlorinated phenols in aqueous solutions with different pH values, the observed IR signals were decreased greatly in pH higher than 6 due to the charged form of chlorinated phenols that were presented. Results of the salt effect indicated that three times stronger of IR signals can be obtained if 20% (w/vol) of NaCl was added.
Chemical Cleaning of Microfiltration Membranes Fouled by Whey
Authors: Madaeni Sayed Siavash , Sharifnia Shahram , Moradi Gholamreza 
Published: May 2015

AbstractMillipore hydrophobic polyvinylidene fluoride (PVDF) microfiltration membranes were used for whey processing. Fouled membranes were cleaned with acid (HCl), alkaline (NaOH) and surfactant (Triton‐X100). The latter resulted in maximum flux recovery and resistance removal. Hydrochloric acid had a moderate effect and sodium hydroxide was the weakest cleaning agent. This is due to the cleaning strength of emulsifiers compared to acid or alkali. However acids are more efficient than alkaline solutions for removal of mineral compounds which remain on the membrane surface.Cleaning efficiency depends on the concentration of cleaning agent being higher for higher surfactant concentration. For acids and alkali, the efficiency increases with increasing the concentration of the reagent reaches a maximum (optimum concentration) and then decreases. This can be explained by changes in permeability of the deposit layer with the concentration of the cleaning agent. Another explanation is the breakage of proteins by acid or alkali which produces more fouling materials and causes less cleaning efficiency.Operating conditions affect the cleaning process. At higher stirring speeds (turbulent flow) or longer cleaning time better removal of deposits and higher cleaning efficiency were observed. The sequential cleaning process may or may not improve the cleaning efficiency. When acidic cleaning was followed by washing with a surfactant an improvement was achieved. This can be attributed to the incomplete removal of deposits by acid. However further cleaning with acid can not improve the cleaning efficiency.During whey processing fouling occurs by deposition of foulants of mostly proteins and macromolecules on the membrane surface or in the membrane matrix. Large substances (compared to the membrane pores) settle on the membrane surface and the small species penetrate and are adsorbed in the membrane pores. Cleaning dissolves and removes the adsorbed foulants from the membrane.
Sesquiterpenes and Flavonoids from Serratula Strangulata
Authors: Dai Jing‐Qiu , Hou Zhen‐Fu , Zhu Qi‐Xiu , Yang Li , Li Yu 
Published: May 2015

AbstractPhytochemistry investigation of the whole plants of Serratula strangulata has led to the isolation of two sesquiterpenes, six flavonoids, and two isoflavonoids. Among these, a sesquiterpene and two flavonoids are new compounds. The structures of these new compounds were elucidated by spectroscopic methods and 2D NMR techniques.
Confined Atoms in Clusters Bubbles Dots and Fullerenes
Authors: Connerade Jean‐Patrick , Kengkan Prasert , Semaoune Rachid 
Published: May 2015

AbstractWe present a brief review of the subject of confined atoms, in which we emphasise the origins of the subject and its most recent applications. Emphasis is placed on the wide variety of situations to which the idealised quantum mechanical treatment is relevant. Both the nonrelativistic and relativistic methods are contrasted; an example of confinement in the Dirac‐Fock scheme is given and some special problems connected with relativistic confinement are mentioned. Finally, we present a discussion of the quantum pressure, and a novel, dimensionless choice of variables which allows universal atomic behaviour for confined atoms to be visualised.
Ion Recoil Following (2+1) REMPI of Nascent Atoms ‐ The Effect on Nascent Velocity Distributions in Velocity Map Imaging
Authors: Parker David H. , Delmdahl Ralph F. , Bakker Bernard B. L. G. , Loock Hans‐Peter 
Published: May 2015

AbstractVelocity map imaging has achieved thus far are solution at 1eV kinetic energy release of ∼30 meV, thus 3% ΔE/E. In order to further improve the resolution we need to look more critically at one of the assumptions in the imaging method–that the conversion of neutral fragments to ionic fragments using the standard REMPI technique does not significantly change the nascent velocity distribution of the neutral species. This is shown in this paper to be a questionable assumption in many cases. The effects of ion recoil due to the detection process in the photodissociation of HI and O2 are predicted to fall in the 2–3% range for normal conditions in velocity map imaging. Recoil effects are illustrated for REMPI of D atoms cooled in a supersonic discharge expansion. Dramatic effects of recoil are also illustrated here for the photodissociation of HI. Recoil effects are shown to play a role in the final resolution of many types of velocity mapping experiments.
An Experimentalist's View of the H− Ion
Authors: Bryant H. C. 
Published: May 2015

AbstractWe present a short survey of selected experimental studies of the negative ion of hydrogen over the past twenty‐three years at the 800 MeV linear accelerator at Los Alamos. Experimental techniques are described and heuristic models are used to explain and motivate experimental results. We discuss the first observations of the 1P resonances just below n = 2, the so‐called “Feshbach” and “shape” resonances, seen in photodetachment. As one experimental question is answered, another question becomes exposed, for example, the effects of electric fields on the spectroscopy of the ion. Techniques used to convert the H− ion into a dual‐beam interferometer moving near the speed of light are described. Experimental data taken near thresh old in an electric field are displayed on a universal plot. Multiphoton detachment extends the spectroscopy of the ion to singlet states that would be unreachable by single photodetachment processes. A thin foil also is used to probe the ion structure. Using ion beams in the 35 kV range, 2‐photon measurements of an isotope shift between Hand D− reveal two‐electron correlation consequences. Finally we ad dress the question, “Why has the shape resonance not been seen in astrophysical observations?
Structure and Dynamics in Alkaline‐earth Atoms
Authors: Aymar Mireille , Lecomte J. M. , Luc‐Koenig E. , Millet M. 
Published: May 2015

AbstractIn this paper we will show how the approach combining the eigenchannel R‐matrix method to the techniques of multichannel quantum‐defect theory (MQDT) is a very powerful method to obtain realistic descriptions of complex spectra of alkaline‐earth atoms in the energy domain and to study the dynamics of various processes in these spectra. Several illustrations will be presented. Those on structure will concern photoionization spectra of barium and strontium at high energy and two‐photon ionization processes in magnesium and strontium. Then, recent results on the dynamics of coherent ionization processes will be presented.
Resonance Scattering in the Three‐Body Systems of Atom‐diatom and Relevance to Condensed Matter Physics
Authors: Salk Sung‐Ho Suck 
Published: May 2015

AbstractThree‐body resonance scattering of atom‐diatomic molecule systems involving internal excitations is discussed by fully allowing the topological phase (Berry phase) contribution. Earlier a generalized formalism (Phys. Rev. A 1996, 53, 2433) of the three‐body resonance scattering was presented by introducing the gauge potential (Berry connection). Based on this study we provide additional information on topological importance in resonance scattering involving the atom‐diatomic molecule systems. The massive gauge field (Berry connection) contribution which arises from a broken symmetry is discussed. Its relevance to condensed matter physics will be briefly high lighted in connection with our recent theory of super conductivity (Phys. Rev. B 1999, 60, 6324).
Q‐Number Essence of the Time and Time‐Energy Uncertainty Relation
Authors: Quang Nguyen Vinh 
Published: May 2015

AbstractIt is proved that time must be a q‐number, which is defended against Pauli's argument indifferent forms. A new form of the commutator of a Hamiltonian with time is presented. The time‐energy uncertainty relation is derived on the same solid basis as the momentum‐position one.
Some Problems in the Theory of Trapping States
Authors: Quang Nguyen Vinh , Phong Pham Hong 
Published: May 2015

AbstractAfter the 1997 Nobel Prize in Physics was awarded to Chu, Cohen‐Tannoudji, and Phillips, great interest returned to both the Bose‐Einstein condensation phenomena and the theory of trapping states. In this present work the mixing‐states principle, which is proved for the case of two arbitrarily degenerate levels by V. Q. Nguyen [Opt. Com. 1985, 5, 335] is extended to a system of three arbitrarily degenerate levels resonantly interacting with the equal‐detuning two‐mode laser field. The theorem for the maximal number of trapping states is proved. The consequence of the theorem is the “for bid den rule”: trapping states do not exist for a V‐system or for the lambda‐type system, in which the sum of the degenerate multiplicity of two low lev els is not greater than one of high level.
Hartree‐Fock Deformed Jellium Calculations for Metallic Clusters
Authors: Lyalin Andrey , Semenov Sergey , Solov'Yov Andrey , Cherepkov Nikolai , Connerade Jean‐Patrick , Greiner Walter 
Published: May 2015

AbstractWe have developed the Hartree‐Fock jellium model for deformed metal clusters by treating the quantized electron motion in the field of the spheroidal ionic jellium background in the Hartree‐Fock approximation. Using this model, we have calculated single electron energy levels as a function of the cluster deformation parameter for a series of sodium clusters with the number of atomsNin a cluster ranging from 4 to 40. We have established that the cluster deformations corresponding to the minimum total energy of the oblate and prolate clusters are in reasonable agreement with the experimental data and the predictions of other theoretical models.
For the Development of Femto Second X‐Ray Laser Using Inner‐Shell L23M1 Transition in Ca
Authors: Kim Dong Eon , Son Sang Hyun , Kim Jae Hoon , Tóth Csaba , Barty Chris P. J. 
Published: May 2015

AbstractA new physical scheme for femto second X‐ray lasers, where the upper lasing is pumped by X‐ray photons and the lower lasing level is depopulated via a Coster‐Kronig radiationless transition, is analyzed for Ca. The transition wave length is 4.1 nm, which is in side the water window. The peak spectral brightness of the X‐ray laser out put at 4.1 nm is predicted to be as large as 5× 1025 photons/sec./(mm2 mrad2 0.1% band width), which is 4 to 5 orders of magnitude brighter than a typical undulator radiation in the similar spectral region. In addition to the high flux, the expected duration of X‐ray lasing of ∼3 fs. will be useful for the study of fast dynamics in physical and biological sciences.
Effects of Imperfect Gate Operations in Shor's Prime Factorization Algorithm
Authors: Guo Hao , Long Gui‐Lu , Sun Yang 
Published: May 2015

AbstractThe effects of imperfect gate operations in implementation of Shor's prime factorization algorithm are investigated. The gate imperfections may be classified into three categories: the systematic error, the random error, and the one with combined errors. It is found that Shor's algorithm is robust against the systematic errors but is vulnerable to the random errors. Error threshold is given to the algorithm for a given number N to be factorized.
Theoretical Study of Electron‐Impact Ionization of He‐Like Ions
Authors: Kuo Tien‐Yow , Huang Keh‐Ning 
Published: May 2015

AbstractWe apply the two‐potential distorted‐wave approximation to study the electron‐impact ionization of He‐like ions. The relativistic and non‐relativistic total cross sections for incident energies from 1 to 10 ionization‐energy units are calculated. Results are compared with other theoretical calculations and experimental data. Systematic behaviors along the isoelectronic sequence are studied.
Doubly Charged Molecular Ions Studied by Double Charge Transfer Spectroscopy
Authors: Furuhashi Osamu , Kinugawa Tohru , Nakamura Nobuyuki , Masuda Suomi , Yamada Chikashi , Ohtani Shunsuke 
Published: May 2015

AbstractWe have developed a double charge transfer (DCT) spectroscope to study doubly charged molecular ions (dications). In the course of the development, DCT spectra of N2, CO, and NO has been ob served with energy resolution of about 0.5 eV. The spectral profiles observed have shown the Franck‐Condon (FC) behavior. We have made an effort to in crease the resolution up to about 140 meV, which is much better than those (1–1.5 eV) reported in previous works. In the present measurement, the vibrationally resolved DCT spectrum for N2++ could be obtained for the first time. The observed peak structures agree well with those calculated using FC factors, differing meaningfully from the spectra taken with Auger electron spectroscopy (AES) and thresh old photoelectrons coincidence (TPEsCO) spectroscopy. The DCT spectroscopy might be a powerful method to study the potential curves of short‐lived dications.