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The structure of the TiVH system is studied by X-ray diffraction and 1 H and 51 V NMR measurements. It is shown that the solid solution of TiV is separated into a few phases by hydrogenation. They are α-TiVH, β-TiVH, γ-TiVH, and γ-TiH phases, which are assumed to have their origins either in TiH x or in VH x . The concentration of each phase can be estimated by NMR, which is dependent on the composition of the system. The phase separation caused by hydrogenation is due to the large stability of the γ-TiH phase.

In a small type spark ignition engines with carburetor, the mixture strength charged into the cylinder, that is, the combustion state and the exhaust characteristics under transient running are remarkable influenced by instantaneous behavior of the fuel liquid-film flowon the inner wall of intake pipe. Accordingly, the authors carried out some experiments and numerical analysis in order to clarify the instantaneous mixture formation in cylinder, under the transient operation as the carburetor throttle valve is stepwise closed.

When alkali metals are brought into contact with silver or gold, catalytic activity for hydrogen activation reactions results which is higher than that for each of the constituent metals. The order of the activity per mole of alkali metal for the H2-D2 exchange reaction is Ag–C>Ag–K>Au–Cs>Ag–Na. The Ag–Cs and Ag–K systems absorb considerable amounts of hydrogen. The nature of the active sites and the contact effect of the IB metal with the alkali metal are discussed.

The behaviors of hydrogen in β‐vanadium hydride VH0.59 were studied by the 1H NMR spectroscopy. Fourier‐transformed spectra, spin‐spin relaxation times, and spin‐lattice relaxation times were measured in the temperature range between 77 and 420 K, and it was found that there are two kinds of hydrogen which occupy different sites over the temperature range studied. The diffusional properties of each component were obtained, and the relation between the components and the superstructures of the hydrogen was discussed.

The behavior of hydrogen in the hydrides of vanadium metal containing small amounts of nickel was studied by 1H NMR spectroscopy. FT spectra and spin-spin and spin-lattice relaxation times for VH0.77, V0.95Ni0.05H0.73, and V0.90Ni0.10H0.65 were measured at temperatures between 77 and 400 K. On the addition of nickel the number of hydrogen atoms on O22 sites decreases and the superstructure of hydrogen is altered. Different effects of nickel on hydrogen diffusion are observed above and below about 200 K, and, therefore, the mechanism of hydrogen diffusion is assumed to change at this temperature.

We have found that the isotropic peak position changes depending on the spinning rate of the sample in 63Cu, 65Cu, 127I, and 79Br magic-angle-sample-spinning (MAS) NMR of cuprous halides, CuI, CuBr, and CuCl. The mechanisms which cause the spinning-rate-dependent shift are briefly discussed.

11 B NMR spectra have been measured for AgIAg 2 OB 2 O 3 glasses over a wide range of composition, and the ratios of fourfold-coordinated borons (BO 4 ) to threefold-coordinated borons (BO 3 ) have been estimated. For [Ag 2 O]/[B 2 O 3 ] ratio ( R a ) less than 1, the fraction of BO 4 ( N 4 ) increases with R a , almost independently of the AgI content. In the region between R a = 1 and 3, N 4 increases with R a for the AgI content lower than 40 mol%, while it decreases for the AgI content higher than 60 mol%. N 4 is almost constant for 40 ≦ [AgI] ≦ 60 mol% in this R a range. For R a = 3, N 4 decreases with the AgI content. Based on the NMR results, we have proposed models of the glass structure, especially in the composition range of high [Ag 2 O]/[B 2 O 3 ] ratios.

High resolution 29Si nuclear magnetic resonance spectra have been measured using magic angle sample spinning technique for several gallosilicates and aluminosilicates with zeolitic structures. The number of gallium atoms coordinating to the SiO4 tetrahedron was determined by the technique in the same manner as established for aluminium in aluminosilicates. The resonance lines were observed to shift to lower field by the substitution of silicon atoms with gallium as well as aluminium. The magnitudes of lower-field shifts were larger for the substitution by gallium than aluminium. The chemical shift ranges of 29Si nuclei are discussed for gallosilicates with the values for aluminosilicates compared.

It is shown that the alloy Ti 0.35 V 0.65 (b.c.c. solid solution) is separated into a few phases by hydrogenation. The structure, concentration and composition of each phase are determined by X-ray diffraction and 1 H and 51 V NMR measurements. It is concluded that the precipitation of titanium dihydride phase is vanishingly small if the hydrogen pressure used in the synthesis of the hydrides is of the order of atmospheric pressure, and it is suggested that high hydrogen pressure favours the precipitation of titanium dihydride.

A phase transition between a monoclinic and a cubic structure takes place in the β phase of Mg2NiH4. The relation between the hydrogen motion and the phase transition in β‐Mg2NiH4 was studied by 1H NMR. FT spectra and spin‐lattice relaxation times were measured in the temperature range across the phase transition. The hydrogen motion is mainly an in‐plane rotation of the NiH4 planar unit in the low temperature form, while it is a hybrid motion of an isotropic rotation of the NiH4 unit and a translational diffusion of the hydrogen atoms beyond the Mg cube in the high temperature form. A good correlation was obtained between the hydrogen motion and the crystal structure, and the origin of the phase transition was discussed.

We have found that the line shape in 31 P magic-angle spinning (MAS) NMR spectra is dependent on the spinning rate of the sample for pyrophosphates and metaphosphates such as Na 4 P 2 O 7 , Na 4 P 2 O 7 ·10H 2 O, Ag 4 P 2 O 7 , and (KPO 3 ) n . The dependence can be explained by spectral spin diffusion of 31 P spins through dipole-dipole interaction.

High-resolution solid-state NMR spectra of 23Na, 27Al, and 29Si nuclei were measured for dehydrated Na–Y type zeolites as well as undehydrated and rehydrated samples using magic angle sample spinning technique. 1H NMR spectra, X-ray diffraction patterns, and thermal properties were measured as well. 23Na NMR results indicate that there are three types of Na sites with different symmetries in the faujasite framework; two types with high and slightly low symmetries are detected by NMR, while the third cannot because of its very low symmetry. Na ions in high-symmetry sites are moved into slightly-low and very-low-symmetry sites by the dehydration. On the other hand, the Na ions in the amorphous region are located in low and very-low-symmetry sites. 27Al and 29Si NMR lines are broadened by the dehydration, due to the distortion of AlO4 tetrahedra and the interaction with 27Al nuclei, respectively. The 29Si spin-lattice relaxation time becomes longer by the dehydration, which indicates that water molecules pla...

High-resolution solid-state 31P NMR spectra have been measured for AgIAg2OP2O5 glasses using magic-angle sample spinning. Three types of PO4 units can be identified: isolated, end chain, and middle chain groups. Quantitative analysis has been carried out for the three groups, and the average length of the PO3 chain has been estimated. The NMR results have confirmed that the network structure is determined by the two components, Ag2O and P2O5, and that AgI does not modify the network.

The 13C nucleus bonded to Br relaxes entirely or partly by the scalar coupling mechanism because the resonance frequency of 13C is close to that of Br and Br is rapidly relaxed by quadrupole interaction. The spin-lattice relaxation curves and the NOE enhancement factors of 13C bonded to Br were measured for compounds with various carbon hybridization, i.e., sp3, sp2, and sp carbons. Then the spin-spin coupling constants between 13C and Br, JCBr, were determined by analyzing the relaxation curves, where the NOE enhancement is taken into account. The JCBr values thus obtained show a number of interesting features, including a notable correlation with the s character of the carbon hybridization.

$^{29}\mathrm{Si}$ nuclear magnetic resonance (NMR) spectra have been measured for amorphous hydrogenated silicon (a-Si:H) and amorphous microcrystalline mixed-phase hydrogenated silicon (\ensuremath{\mu}c-Si:H) using high-resolution solid-state NMR techniques; magic-angle sample spinning, dipolar decoupling, and cross polarization (CP). $^{1}\mathrm{H}$ NMR spectra have been also measured. The peak position of the $^{29}\mathrm{Si}$ signal observed with the CP technique correlates well with the line shape of $^{1}\mathrm{H}$ NMR spectra, which has been ascribed to a chemical shift due to bonding configurations not only in the first coordination sphere but also in the second- and further-nearest coordination spheres. Origins of the $^{29}\mathrm{Si}$ linewidth have also been discussed, the magnitude of each contribution being estimated. A narrow $^{29}\mathrm{Si}$ signal can be obtained without the CP technique only in \ensuremath{\mu}c-Si:H, which demonstrates that there are regions where the silicon network is mobile. Based on the NMR results, microscopic models of the structures of a-Si:H and \ensuremath{\mu}c-Si:H are presented.

The behavior of hydrogen in glow-discharge (GD) μc-Si:H has been characterized by 1 H NMR. The 1 H spectra consist of two components with different linewidths. The linewidth (FWHM) of the narrow component is about 0.5 kHz at ν 0 = 90 MHz, being much narrower than has been observed in GD a-Si:H deposited under a conventional low RF-power condition. It has been demonstrated that the 0.5-kHz FWHM component originates from the hydrogens in motional narrowing state, and such fast-moving hydrogens are incorporated both in μc-Si:H and high-power deposited a-Si:H.

Hydrogen distribution in the low-temperature phase of Mg2NiH4 is discussed, based on 1H NMR results. Square planar and tetrahedral distributions around a nickel atom are considered as structural models, and the 1H NMR results support the former.

Summary To test the hypothesis that the frequencies of normal alleles (ANs) with a relatively large number of CAG repeats (large ANs) are related to the prevalences of the dominant spinocerebellar ataxias (SCAs)—SCA types 1, 2, 3 (Machado-Joseph disease), 6, and dentatorubral-pallidoluysian atrophy (DRPLA)—we investigated the relative prevalences of these diseases in 202 Japanese and 177 Caucasian families and distributions of the number of CAG repeats of ANs at these disease loci in normal individuals in each population. The relative prevalences of SCA1 and SCA2 were significantly higher in Caucasian pedigrees (15% and 14%, respectively) than in Japanese pedigrees (3% and 5%, respectively), corresponding to the observation that the frequencies of large ANs of SCA1 (alleles >30 repeats) and of SCA2 (alleles >22 repeats) were significantly higher in Caucasians than in Japanese. The relative prevalences of MJD/SCA3, SCA6, and DRPLA were significantly higher in Japanese pedigrees (43%, 11%, and 20%, respectively) than in Caucasian pedigrees (30%, 5%, and 0%, respectively), corresponding to the observation that the frequencies of large ANs of MJD/SCA3 (>27 repeats), SCA6 (>13 repeats), and DRPLA (>17 repeats) were significantly higher in Japanese than in Caucasians. The close correlations of the relative prevalences of the dominant SCAs with the distributions of large ANs strongly support the assumption that large ANs contribute to generation of expanded alleles (AEs) and the relative prevalences of the dominant SCAs.

29Si nuclear magnetic resonance (NMR) spectra have been measured for amorphous hydrogenated silicon as well as amorphous‐microcrystalline mixed‐phase hydrogenated silicon using cross polarization and magic‐angle sample spinning. 1H NMR spectra have been measured as well. The peak position of the 29Si signal has been found to correlate well with the line shape of the 1H NMR spectra, and mechanisms determining the position have been discussed.

The existence of two kinds of hydrogen in VH0.59 and their composition were clarified by pulsed NMR spectroscopy of 1H in the temperature range between 120 and 350 K. The energy difference between them is about 8.0 kJ mol-1.

In order to investigate the corelation between dangling bonds and hydrogens in a-Si:H, electron-nuclear double resonance (ENDOR) experiment has been employed on undoped a-Si:H films before and after isochronal annealings. It has been demonstrated through the analyses of ENDOR as well as ESR and NMR that in high ESR spin-density sample the dangling bonds are coupled mainly with hydrogens corresponding to the broad component of NMR, while those are with the narrow component in low ESR spin-density sample.

High-resolution solid-state NMR spectra of 23Na, 27Al, and 29Si nuclei were measured for dehydrated Na–Y type zeolites as well as undehydrated and rehydrated samples using magic angle sample spinning technique. 1H NMR spectra, X-ray diffraction patterns, and thermal properties were measured as well. 23Na NMR results indicate that there are three types of Na sites with different symmetries in the faujasite framework; two types with high and slightly low symmetries are detected by NMR, while the third cannot because of its very low symmetry. Na ions in high-symmetry sites are moved into slightly-low and very-low-symmetry sites by the dehydration. On the other hand, the Na ions in the amorphous region are located in low and very-low-symmetry sites. 27Al and 29Si NMR lines are broadened by the dehydration, due to the distortion of AlO4 tetrahedra and the interaction with 27Al nuclei, respectively. The 29Si spin-lattice relaxation time becomes longer by the dehydration, which indicates that water molecules pla...

When alkali metals are brought into contact with silver or gold, catalytic activity for hydrogen activation reactions results which is higher than that for each of the constituent metals. The order of the activity per mole of alkali metal for the H2-D2 exchange reaction is Ag–C>Ag–K>Au–Cs>Ag–Na. The Ag–Cs and Ag–K systems absorb considerable amounts of hydrogen. The nature of the active sites and the contact effect of the IB metal with the alkali metal are discussed.

The amount of intake air in a two-stroke motorcycle engine was studied by considering the influences of atmospheric conditions and various engine factors, taking note of inertial limitation on the maximum delivery ratio. The influence of the intake and exhaust pipes was determined by considering the following: pressure at the entrance of the intake pipe, boost pressure, atmospheric temperature, mixture ratio, and back pressure. The influence of engine dimensions was determined by considering carburetor opening, dimensions of intake pipe, crankcase volume, engine size, and port opening period. Theoretical results correspond fairly well with experimental data.

Etude des caracteristiques de frein-moteur d'un moteur deux temps a compression dans le carter du vilebrequin

The behaviors of hydrogen in β‐vanadium hydride VH0.59 were studied by the 1H NMR spectroscopy. Fourier‐transformed spectra, spin‐spin relaxation times, and spin‐lattice relaxation times were measured in the temperature range between 77 and 420 K, and it was found that there are two kinds of hydrogen which occupy different sites over the temperature range studied. The diffusional properties of each component were obtained, and the relation between the components and the superstructures of the hydrogen was discussed.

To determine definitely the transient characteristics of smoke emission from a diesel engine, it is necessary to know details of its power transmission elements such as fuel injection system, combustion process, engine rotating system and its friction losses. Previous studies have been unclear about the relations between the engine performance, smoke characteristics and influence of operating conditions, especially on the two-cycle engine. Therefore, the authors carried out the experiments while changing its brake load and fuel pump rack, respectively, to examine the effects of the operating conditions on the exhaust smoke density under transient operations. (A) For the covering abstract see IRRD 865952.

The behavior of hydrogen in vanadium hydride at high hydrogen concentration in the bct‐lattice phase was studied by 1H NMR spectroscopy. Three kinds of hydrogen were observed in VH0.77, where some kinds of superstructures of hydrogen are formed. Their structures are proposed by analogy with the β1‐V2H superstructure, and the occupation of the tetrahedral site is suggested. (AIP)

A method is proposed by which the composition of the two kinds of hydrogen with different diffusional behavior in metal hydrides can be determined accurately by means of 1H NMR; using the method, it is found that the energy difference between the two sites occupied by the two kinds of hydrogen is 7.9 kJ/mol in VH0.77.

27Al NMR spectra of hydrated aluminum nitride ultafine powder, measured using magic angle sample spinning technique, showed two peaks which can be attributed to Al coordinated by four N atoms and to Al coordinated by six O atoms, and the hydration process was discussed.

The high-resolution solid-state 13C, 29Si, 31P, 23Na, 27Al, and 11B NMR spectra of several compounds have been measured using magic-angle sample spinning. Their isotropic chemical-shift values have been determined accurately to use as shift references in solid-state NMR; this makes comparison between literature shift data possible.

29Si nuclear magnetic resonance spectra have been measured for amorphous-microcrystalline mixed-phase hydrogenated silicon (µc-Si:H) and amorphous hydrogenated silicon (a-Si:H), using cross-polarization and magic-angle sample-spinning techniques. A narrow 29Si signal with a width of 9 ppm can be obtained without the cross polarization technique only in µc-Si:H, which suggests that moving Si atoms are present in µc-Si:H, while not in a-Si:H.

31P nuclear magnetic resonance (NMR) spectra have been measured for amorphous hydrogenated silicon heavily doped with phosphorus. Phosphorus is enriched in the film during glow-discharge decomposition of the SiH4-PH3 mixture at a substrate temperature of 250°C by a factor of 3. 31P NMR results demonstrate that almost all the phosphorus atoms are bonded to three silicon atoms, and not to hydrogen or to other phosphorus.

The motional properties and thermal stabilities of proton-containing species adsorbed on an ultra-fine powder of aluminum nitride were studied by means of 1H NMR and are here discussed along with a structural model.