bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mesophases I
Authors: Ogilvie J. F. 
Published: June 2015

AbstractIn this review of the properties and applications of mesophases, after a general description of the states of aggregation of matter, the types of liquid crystals are distinguished. The thermotropic liquid crystals are classified on the basis of their structural properties. A comparison of sets of chemically related molecules indicates how details of molecular structure (topology and conformation) affect the existence and sequence of mesophases for the lath‐like thermotropic mesogens.
Relaxations Studies of 2IZSZ Spin Order with Signal Enhancement by Coherence Transfer
Authors: Chang Wen‐Tsung , Hwang Lian‐Pin , Wang Pei‐Lejn 
Published: June 2015

AbstractThe pulse sequence for generating coherence transfer (or polarization transfer) is invoked to enhance the signal of heteronuclear two spin order (e.g. 2IZSZ) in a spin system with CH moiety. This allows the observation of selective conversion of Zeeman order, in a sample with natural abundant 13C nuclei, into two spin order for measuring cross‐correlation of chemical shift anisotropy and dipole‐dipole interactions. The molecular reorientational correlation time and the orientation of the C–H axis with respect to the principal axes of carboxyl CSA tensor may be determined simultaneously in the relaxation profile of two spin order.
Sequence Determination of a Tetrapeptide Using Long‐Rang Heteronuclear Shift Correlation 2D NMR Spectroscopy
Authors: Shi Fong‐Ku , Lin Ying‐Chih , Wang Kung‐Tsung 
Published: June 2015

AbstractA tetrapeptide has been studied by means of NMR of 13C in natural abundance. By the combined application of various two‐dimensional 1H/1H and 13C/1H correlation techniques, the primary structure of the peptides could be unambiguously determined.
Electrophilic Reactions of Dithio‐Substituted o‐Methoxycinnamyllithium
Authors: Chen Ming‐Yi , Fang Jim‐Min 
Published: June 2015

AbstractThe dithio‐substituted o‐methoxycinnamyllithium 3L reacted at the α‐site with D2O and most of carbonyl compounds in extents of 70–100 %. while it reacted with halides at either the α or γ‐site, depending on the nature of respective halide.
Mesophases II
Authors: Ogilvie J. F. 
Published: June 2015

AbstractIn the continuation of a review of the classification, properties and applications of mesophases, the general features of thermodynamic data of thermotropic liquid–crystalline phase transitions are surveyed. The orientation of molecules in liquid–crystalline mesophases is discussed in relation to the electrical properties. Some applications of mesophases are outlined. After surveys of both the structural classes of lyotropic mesophases and the properties of plastic crystals in cubic phases, the thermodynamic, structural and other properties of all mesophases‐are summarily considered in relation to the present state of the knowledge in this field.
Adsorption/Thermal Desorption with Tenax‐GC for the Collection and Analysis of Polycyclic Aromatic Hydrocarbons and Chlorinated Compounds
Authors: Sye Wen‐Fa , Chang Chin‐Liang 
Published: June 2015

AbstractA system for the determination of polycyclic aromatic hydrocarbons(PAHs) and chlorinated compounds in air by means of adsorption/thermal desorption(ATD) with small bed volume (0.1 g) Tenax cartridges, followed by cryogenic trap in a U‐shaped stainless steel tube with liquid nitrogen as an appropriate concentration method prior to capillary gas chromatography is described. Recoveries were determined for the complete ATD method. Desorption recoveries near 100% were found for a variety of chlorinated compounds and polycyclic aromatic hydrocarbons.
Analysis of Seven Herbicides by Gas‐Liquid Chromatography
Authors: Wang Wan‐Kung , Huang Shang‐Da 
Published: June 2015

AbstractSimutaneous analysis of seven commonly used herbicides, 2,4‐D methyl ester, 2,4‐D methyl ester, 2,4,5‐T methyl ester, silvex methyl ester, ramrod, CIPC and DEF, by gas‐liquid chromatography with an electron capture detector was attempted. Two packed columns (which are generally used for the analysis of chlorinated pesticides) and two chemically bonded fused silica capillary columns were used for the analysis. When the packed columns were used, ramrod always interfered with the analysis of 2,4‐D methyl ester and/or silvex methyl ester. Complete separation with reasonable analysis time can be achieved using one of the chemically bonded fused silica capillary columns.
The Photochemistry of Ch3I in Various Matrices at Low Temperature
Authors: Yeh Syun‐Ru , Chang Hua 
Published: June 2015

AbstractThe photodissociation of methyl iodide in various matrices at low temperature was studied. The observed Raman spectra excited by 514.5 nm laser radiation showed that there were two different photolytically produced iodine species isolated in the matrices after illumination by a medium pressure mercury lamp. One species which was dominant at lower iodine concentrations and exhibited a progression with an ωe of 201 cm−1, belonged to the matrix isolated iodine monomer (I2). The other species, which was dominant at higher iodine concentrations with an ωe of approximately 180 cm−1, belonged to the iodine aggregate ((I2)n). Five progressions of resonance Raman or resonance fluorescence of these two species were also observed in the other matrices. The iodine aggregate in the methyl iodide matrix at 77 K was formed in a crystalline structure, while the photolytically generated iodine aggregate from CH3I/Ar (2/3) matrix at 10 K, after illumination with a mercury lamp, was in amorphous form. The rearrangement of photolytically produced iodine aggregate in methyl iodide matrix was observed as a function of the duration of illumination. Local heating effects of the laser radiation might induce the iodine monomer to aggregate in matrices. The photodissociation mechanism of methyl iodide in matrices is also proposed.
Current Developments in Optical Emission Spectrometry with High‐Frequency and Microwave Induced Plasmas
Authors: Broekaert J.A.C. 
Published: June 2015

AbstractThe state‐of‐the‐art and trends of development with the inductively coupled plasma (ICP) and microwave induced plasmas (MIP) as radiation sources for optical emission spectrometry arc presented. Especially techniques for sample introduction are discussed. Here special reference is given to the use of spark ablation as well as 10 direct sample insertion and slurry atomization for the direct analysis of powder samples. The development in MIP optical emission Spectrometry is shown to center on the improvement of the plasma sources, their characterization and their tailoring to various sampling techniques. Results of the use of pneumatic nebulization of liquids and electrothermal evaporation of dry solution residues will be presented.
Standard Chemical Thermodynamic Properties of Perfluoro N‐Alkanes
Authors: Wen Chung‐Ming 
Published: June 2015

AbstractThe chemical thermodynamic properties Cp°, ΔHf° S°, ΔGr° and Kp of gaseous perfluoro n‐alkanes, P(CF2)n F(2≤n≤10), have been calculated from 298.15 to 1000 K using the Benson method with Cp° = a″;b/T + c/T2, Cp°=a+bT+c+/T2 and Cp°=a″ + bT +cT2. Better results are obtained for Cp°=a+b/T+c/T2. The calculated chemical thermodynamic properties of C2 F6 (g) are in excellent agreement with the literature data of Stull, Westrum, and Sinke under IBM/PC microcomputer with STEP data base management system.
Axial and Equatorial Dimethylamine Substitution on Phosphorus in the 1,3,2‐Oxazaphosphorinane Ring System: Structures of 2‐Dimethylamino‐4‐Phenyl‐2H‐1,3,2‐Oxazaphosphorinane‐2‐Oxides
Authors: Liu Ling‐Kang , Shih Yun‐Er , Li Yann‐Shiang 
Published: June 2015

AbstractSingle crystal x‐ray structures of the diastereomeric 2‐dimethylamino‐4‐phenyl‐2H‐1,3,2‐oxazaphosphorinane‐2‐oxides, 5c and 6c, have been determined. The pair has been prepared in a straightforward manner by reaction of 3‐amino‐3‐phenylpropanol with Mo2P(O)Cl2, and separated into pure forms by column chromatography. Crystal data of 5c: space group P21/n, a = 11.087(3), b = 6.087(6), c = 18.465(6)Å, β = 98.40(3)°, R = 0.035 for 1845 reflections. Crystal data of 6c: space group P21/n, a = 11.176(2), b = 6.893(2), c = 16.673(3)Å, β = 95.29(1)°, R = 0.037 for 1253 reflections. The fast‐migrating 5c is cis (Ph and P = O group cis) with the configuration of 2RS, 4SR. The slow migrating 6c is trans with the configuration of 2RS, 4RS. In both structures the 1,3,2‐oxazaphosphorinane rings are chair like with the P‐end essentially flattened, The skeleton made up with 4‐phenyl‐1,3,2‐oxazaphosphorinane is essentially the same. With a conformationally demanding 4‐phenyl substituent, 5c has an axial Mc2N whereas 6c has an equatorial Me2N. For 6c, the exocyclic P‐N bond has a partial double bond character the geometry about exocyclic N is planar. On the other hand, for 5c, the geometry about exocyclic N deviates considerably from planarity, the sum of the angles around N being 348.1°. In the crystalline state, the screw‐related 5c molecules are hydrogen bonded whereas in the crystalline state, the centro‐symmetrically related 6c molecules are paired‐up by hydrogen bonds, both through the N‐H and P = O system.
New Developments in Activation Analysis for Material and Environmental Sciences
Authors: Alfassi Zeev B. 
Published: June 2015

AbstractActivation analysis in general and mainly reactor neutron activation analysis (NAA) has been used extensively for measuring trace elements in high purity materials, particularly semiconductor materials. The advantages of NAA in determination of trace elements differ from one semiconductor material to another. For all of them the inherent properties of activation analysis especially those of non contamination with the reagents, low blanks and high sensitivity are the reasons for the choice of NAA as the main analytical procedure. These inherent properties are essential for analysis of high‐purity materials where concentrations of ppb's and sub ppb's have to be measured.NAA is specially suitable for the determination of trace elements in silicon due to the very short lived very low activity induced by neutron reaction in silicon. This enables easy instrumental (i.e. without chemical separations) determination of trace elements in silicon. In the HFR reactor at Peten, Netherlands, a special facility was constructed for irradiation of silicon samples of Philips, in which silicon wafers of up to 15 cm diameter can be irradiated with 4 × 1013n. cm−2. sec−1 and the irradiation is done for 72–96 hours. using large Ge(Li) detectors (100 to 150cc) and long counting time (8–16 hours) they measured 22 elements in concentrations below ppb and 10 others between ppb and 300 ppm. Trace elements in germanium have been determined both instrumentally after very long decay time (100 days) or after short decay time removing the activities from the matrix by chemical separation. Trace elements in GaAs are determined only after chemical separtion. Several other semiconductor material such as Sc, Te, GaP and CuInS2 were also determined by NAA.Some trace elements cannot be determined by neutron activation. Carbon, nitrogen and oxygen are determined by activation with protons, alphas or 3He particles. Boron and hydrogen are determined by prompt emission induced by charged particle activation, which gives not only the total concentration but also the depth profile. Carbon, nitrogen, oxygen and phosphorus were also determined by prompt proton activation analysis.The environmental samples studied by activation analysis can be divided into three categories: atmospheric aerosols, water samples and solid wastes. NAA of atmospheric aerosols have been used for their posible toxicological hazards, their source identification and for studies of atmospheric transport processes.
NMR and Molecular Genetics as Tools for Investigating Protein Interactions in Membrane Systems
Authors: Pratt E. A. , Ho Chien 
Published: June 2015

AbstractIn our laboratory, we have applied the tools of nuclear magnetic resonance (NMR) spectroscopy and molecular genetics to investigate the structural and dynamic properties of membrane‐associated proteins and their interactions with membrane components. There are two general classes of membrane proteins, i.e., intrinsic and peripheral ones. For the intrinsic membrane proteins, we have chosen the membranebound D‐lactate dehydrogenase (D‐LDH) of Escherichia coli as a model to study protein‐lipid interactions in membranes. D‐LDH is a respiratory enzyme of molecularweight 65, 000 containing flavin adenine dinucleotide (FAD) as a cofactor. The activity of purified D‐LDH is enhanced up to 100‐fold by lipids and detergents. The gene for D‐LDH has been sequenced, and production of the enzyme amplified up to 300‐times normal levels. We have biosynthetically incorporated 5‐fluorotryptophan (5F‐Trp) into D‐LDH and studied the five Trp residues by 19F‐NMR spectroscopy. In order to gain additional information using 19F‐NMR, site‐specific, oligonucleotide‐directed mutagenesis has been used to insert a sixth Trp into D‐LDH at various positions throughout the 571‐amino acid chain. These mutant D‐LDHs are being characterized biochemically and through NMR. For peripheral membrane proteins, we have chosen two periplasmic binding proteins, histidine‐binding protein J (J protein) of Salmonella Typhimurium and glutamine‐binding protein (GlnBP) of E. coli as models to investigate the structure‐function relationship in periplasmic binding protein‐mediated active transport systems. These two proteins both have molecular weights of approximately 25, 000. By using mutant J proteins and GlnBPs and site‐specific, oligonucleotide‐directed mutagenesis techniques, we have assigned several resonances to specific amino acid residues. We are investigating the relationship between ligand‐induced conformational changes in these two proteins and their roles in the active transport of ligand across the cell membrane. We have found that a combination of isotopic labeling, biochemistry, molecular biology, and NMR is a very useful approach to investigate various interactions of membrane‐associated protein systems.
Cathodic Action of Uranyl‐5‐Sulfosalicylate Complexes at Dropping Mercury Electrode
Authors: Chen Shou‐Nen , Gi Hung‐Jang , Li Ding‐Tzay 
Published: June 2015

AbstractThe uranyl ion in 5‐sulfosalicylic acid (5‐SSA) solution has been investigated by polarography. The constitution of the chelate species was confirmed by conductometric titration, under the experimental conditions: temperature 25±0.1C. pH = 2.0‐9.0. ligand concentration 10‐200 mM. At pH < 4.8, the chelate species, UO2(HA)22−, is predominant. At pH 6.0. the complex species. UO2(A)24 mainly exists. The chelate species. UO2(HA)22−, and UO2(A)24, co‐exist between pH 4.8‐6.0. The diffusion coefficients and stability constants have been determined by equations derived from Ilkovic equation.
Studies of Photon Correlation Spectroscopy of the Microemulsion of H2O/Tween 80/Benzene Derivative
Authors: Hwang Jeng Shung , Gi Hung Jang , Wu Pailin , Chen Shou Nan 
Published: June 2015

AbstractThe microemulsion of the H2O/Tween 80/benzene derivative (C6H6, CH3C6H5, NO2C6H5 and NH2C6H5) was investigated by the technique of Photon correlation spectroscopy. Autocorrelation data were measured at 90 scattering angle and were analyzed by using a quadratic fit and linear fit. The quadratic fit was found to describe all Properties better than the linear fit, and thus the linear fit was limited to the region of very short sampling time. When the amount of benzene derivative added to the sample solution was lower than Vmax, the Z‐average mean radius, <r>z, and the polydispersit Y, μ2/Γ2, increased as the amount of benzene derivative was increased. When the amount of benzene derivative was larger than Vmax, the aqueous and organic phases separated and the <r> z, and μ2/Γ2 of all phases remained constant. Emulsification did not occur in the organic phase of the H2O/Tween 80/aniline system. When we adjusted the Tween 80 concentration, it was found that <r>z and μ2/Γ2 decreased as the Tween 80 concentration increased.
Conducting Polymer–Synthesis and Properties of an Unsymmetrical Disubstituted Polyacetylene–Polyiodocyanoacetylene
Authors: Hsieh Bor‐Tsung , Jiang George Jang‐Jyi 
Published: June 2015

AbstractThe unsymmetrical disubstituted acetylene, iodocyanoacetylene (ICA), can be polymerized at 140°C in the solid state in high yield. The resulting polymer, polyiodocyanoacetylene (PICA), is a black lustrous stripe having the structure of . If the polymerization temperature is raised above 160°C, part of the iodine will split off from the polymer. However, at higher temperatures, the cyclization reaction occurs and the ladder polymer is formed. The conductivities of the pristine‐PICA and its ladder polymers are all in the semiconductor region.
Speciation, Catalysis and Transmetallation of Manganese Tetrakls(N‐Methyl‐4‐Pyridyl)Porphlne in Aqueous Media
Authors: Lin Ching‐Yao , Lin Zui‐Feng , Hseu Tong‐Ming , Oliver Su Y. 
Published: June 2015

AbstractThe electrochemistry and spectroelectrochemistry of manganese tetrakis(N‐methyl‐4‐pyridyl)porphine (Mn‐TMPyP) in aqueous media have been studied. For MnIIITMPyP two water molecules ligate to the metal center and the formation constant(β2) is 0.11 in acetonitrile solution. The pKa1 and pKa2 for MnIIIIMPyP(H20)2 are 10.9 and 12.3, respectively in aqueous media. There is only one pKa at 11.7 for MnIIIMPyP(H2O)2. The pKa of the oxo‐manganese(IV) porphyrin, O = MnIVTMPyP(H2O), is 11.3. MnIITMPyP demetallates rapidly to free base in acidic aqueous solution. MnIITMPyP also undergoes electrocatalysis for oxygen reduction. In acidic conditions, demetallation and catalysis rates are competitive. The transmetallation of MnTMPyP by Zn2+ can be achieved in the presence of thiols. The UV‐Visible spectra in the reaction process suggest that the formation of some reactive intermediate is essential for the transmetallation.
Mixed Ligand Complexes of Ni(II) with Arylidene‐ Anthranilic Acids and Some Lewis Bases
Authors: Ibrahim S.A. , El‐Gyar S.A. , El‐Gahami M.A. , Hammam A.M. 
Published: June 2015

AbstractSome binary and ternary complexes of Ni(II) with arylideneanthranilic acids and Lewis bases have been prepared and characterized by elemental analyses, IR spectra and X‐ray powder diffraction. On the basis of the IR spectra it was found that the Schiff bases used act as monobasic bidentate ligands except for the ortho‐hydroxy derivative which acts as a dibasic tridentate ligand. From X‐ray analysis it is concluded that the binary Ni(II) chelates are isostructural, and the ternary Ni(II) complexes are also isostructural.
Spectral Properties of Bifunctional Schiff Bases, [Bis (X‐Phenyl)‐Ethane Diimine]
Authors: Mahmoud M.R. , El‐Nady A.M. , Abu El‐Wafa M. , Rabi U.M. 
Published: June 2015

AbstractElectronic spectra of five (Bis(X‐phenyl)‐Ethane diimine] compounds I‐V, have been investigated in various organic solvents and aqueous buffer solutions of varying pH's. The observed visible band is assigned to intramolecular CT transition. Furthermore, it is deduced that structure of the o‐hydroxy derivative is not entirely planar. The acid dissociation constant values of the hydroxy derivatives have been determined and are discussed.
Separation of Uranium Mixing with its Decayed Nuclides and its Activated Nuclides
Authors: Wu Kuen‐Li , Lo Jem‐Mau 
Published: June 2015

AbstractExtractions of uranium from the acidic media, HCl and MNO3 at different concentrations, by the tertiary amines, trilaurylamine, triisooctyllamine and trioctylamine were systematically investigated. In experiments, 232U was used as the tracer and aliquots of both phases after extractions were taken, ashed at 500°C, placed onto stainless steel planchets, and measured by a surface‐barrier Si(Li) detector connected to an alpha spectrometer. One unique condition found useful for complete separation of uranium was that of the radioactive uranium present in 8 M HCl being extracted with 10% trilaurylamine in xylene. In that case, greater than 95% of the uranium could be extracted into the organic solution, whereas all of the radionuclides of a series of its decayed products, 228h, 224Ra, 220Rn, 216Po and 212Bi remained completely in the aqueous solution. The same procedure could also be used for the separation of uranium from a mixture with its activated nuclides. Plutonium‐239 and Am were used as the tracers representing the activated nuclides of uranium. It was found that 241Am was absolutely not extracted, but that 239Pu could be extracted with ≥95% efficiency from the medium of 8 M HCl into 10% trilaurylamine in xylene. However, 239Pu could be easily stripped using the solution mixture of 8 M HCl and 0.05 M NH4I and excluded from the organic solution.
Proton NMR Studies of the Electronic Effect of Substituents at the Azomethine Carbon of N,N′‐Bisethylene (Salicylideniminato) Cobalt (II) Complex
Authors: Cheng Cheu‐Pyeng , Hwang Yaw‐Shing , Hwang Ruey‐Shyan 
Published: June 2015

AbstractThe proton paramagnetic shifts of low spin N,N′‐ethylenebis(salicylideniminato)cobalt(II) and its derivatives were studied to understand the effect of substituents at the azomethine carbon on the electronic structure of the Schiff‐base cobalt complexes. Analysis of the 1H paramagnetic shifts of H and CH3 bonded to the azomethine carbon reveals that spin delocalization through a interaction is responsible for the contact contribution to the paramagnetic shift. When the phenyl group is bonded to the azomethine carbon, the plane of the phenyl group is perpendicular to the plane of the complex and the phenyl group makes a negligible contact contribution to the paramagnetic shift.
The Chemisorptive Properties of Nickel Borides
Authors: Chen Yin‐Zu , Wu Jong‐Shiun 
Published: June 2015

AbstractThe chemisorptive properties of the nickel borides have been studied with temperature programmed desorption of H2and CO. The TPD chromatograms of H2show two major peaks at 150°C and 300°C for the P‐1 and P‐2W nickel borides and a major peak at 150°C for the DBNi and CrP‐1 nickel borides. Not all hydrogen molecules are dissociatively adsorbed on surface nickel, some hydrogens diffuse and are absorbed into the matrix of the nickel borides. Except the Cr‐promoted P‐1(P‐2W), the nickel borides do not exhibit the obvious chemisorptive capacity for CO. The Cr‐promoted nickel borides, on the other hand, not only have the obvious uptake capacity for CO but also have the good activity for CO dissociation.
Some Novel Thiazoline and Thiazolidinone Derivatives Surmounted on Substituted Pyrazole Moieties as Potential Antipyretic Agents
Authors: Farghaly A.M. , Chaaban I. , El‐Khawass S.M. , Fahmy S. M. 
Published: June 2015

AbstractSix novel series of substituted thiazoline (V, VI, VII and VIII) and thiazolidinone derivatives (IX and X) resulting from 2,3‐dihydro‐1, 5‐dimethyl‐3‐oxo‐2‐phenyl‐1H‐pyrazole‐4‐carbaldehyde (I) and 1‐phenyl‐3‐p‐tolyl‐1H‐pyrazolc‐4‐carbaldehyde (II) were synthesized. The course of this synthesis included the preparation of two new scries of disubstituted thiosemicarbazone precursors (III and IV) which were cyclized with phenacyl bromide, ethyl 2‐chloroacetoacetate as well as ethyl bromoacetatc to afford the target thiazolines and thiazolidinoncs. The antipyretic activity of some representative compounds was performed.
Some Cyclization Reactions with 1,3‐Diphenyl‐5‐Imino‐2‐Imidazolidinone‐4‐Thione
Authors: Mohamed Y.A. , Ammar Y.A. , Sh. El‐Sharief A.M. , Aly M.M. 
Published: June 2015

Abstract1,3‐Diphenyl‐5‐imino‐2‐imidazolidinone‐4‐thione (II) was treated with diazomethanes to give (III‐V). Interaction of (II) with amino compounds furnished the corresponding 4‐substituted imino derivatives (VIa‐m). Imidazoquinoxaline derivatives (VIIIb, c) were obtained through interaction of (II) with o‐phenylenediamines. Condensation of (II) with hydrazines afforded the hydrazones (IX, Xa, b). Semicarbazone and thiosemicarbazone derivatives (XIIa‐d) were prepared from the reaction of (IX) with isocyanates and isothiocyanates. Again (II) was allowed to react with n‐butylmagnesium bromide and HgCl2 to give (XIII) and (XIV) respectively.