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891.
Vibration-rotation spectra and molecular force field of methylene fluoride and methylene fluoride-d2
Infrared spectra of CH2F2 and CD2F2 have been measured under a medium resolution. The vibration-rotation bands of CD2F2 fundamentals have been analyzed and the assignment for the fundamentals of CD2F2 is given. In addition, a number of overtone and combination bands are observed for CH2F2, which helps to clarify the vibrational assignment for CH2F2. A normal coordinate treatment has been carried out: The force constants in a modified Urey-Bradley as well as the general valence force fields have been determined, the vibrational frequencies and the centrifugal distortion constants obtained from microwave spectroscopy being used. The force constants of the methylene fluoride molecule are discussed in connection with those of the related molecules. Special features of the CH2F2 and CD2F2 spectra are also described. 相似文献
892.
893.
Jiang ZH Tanaka T Iwata H Sakamoto S Hirose Y Kouno I 《Chemical & pharmaceutical bulletin》2005,53(3):339-341
Three new ellagitannins named balanophotannins A-C having a 1,1'-(3,3',4,4'-tetrahydroxy)dibenzofurandicarboxyl group in their molecules and four known lignan glycosides were isolated from the extracts of fresh aboveground and underground parts of a medicinal parasitic plant Balanophora japonica (Balanophoraceae). Their structures were elucidated on the basis of spectral and chemical evidence. Chemotaxonomic significance of the known lignan glycosides in Balanophora japonica was discussed. 相似文献
894.
895.
896.
Riede T Mitchell BR Tokuda I Owren MJ 《The Journal of the Acoustical Society of America》2005,118(1):514-522
Measuring noise as a component of mammalian vocalizations is of interest because of its potential relevance to the communicative function. However, methods for characterizing and quantifying noise are less well established than methods applicable to harmonically structured aspects of signals. Using barks of coyotes and domestic dogs, we compared six acoustic measures and studied how they are related to human perception of noisiness. Measures of harmonic-to-noise-ratio (HNR), percent voicing, and shimmer were found to be the best predictors of perceptual rating by human listeners. Both acoustics and perception indicated that noisiness was similar across coyote and dog barks, but within each species there was significant variation among the individual vocalizers. The advantages and disadvantages of the various measures are discussed. 相似文献
897.
Takayama K Koseki K Torikai K Tokuchi A Nakamura E Arakida Y Shimosaki Y Wake M Kouno T Horioka K Igarashi S Iwashita T Kawasaki A Kishiro J Sakuda M Sato H Shiho M Shirakata M Sueno T Toyama T Watanabe M Yamane I 《Physical review letters》2005,94(14):144801
A single rf bunch in the KEK proton synchrotron was accelerated with an induction acceleration method from the injection energy of 500 MeV to 5 GeV. 相似文献
898.
The effects of the positron (e(+)) annihilation in e(+) scattering by the H atom are included directly in the Hamiltonian as an absorption potential, and hence the finite lifetimes Gamma(ns) of positronium (Ps) in states ns are automatically taken account of. The Schr?dinger equation is solved using the hyperspherical close-coupling method. The annihilation and Ps formation are shown to be inseparable near the Ps(1s) threshold E(th); Ps formation constitutes just an indirect pathway to annihilation. The annihilation cross section, which would diverge near E(th) if Gamma(1s) were infinite, connects smoothly across E(th) to the cross section for Ps formation, which is meaningful only at energies well above E(th). 相似文献
899.
Isao Yamada Kakuei Matsubara Mitsuharu Kodama Masahide Ozawa Toshinori Takagi 《Journal of Crystal Growth》1978
The main characteristics of the metal films deposited by ionized-cluster beam deposition and their applications are described. These films showed good adhesion, high packing density, good conductivity, and unique diffusion characteristics of the deposited material onto Si substrates. These advantages have been utilized in fabricating electron devices such as flexible circuits, solar cells, and ohmic contacts. 相似文献
900.
Kobayashi K Fukuhara H Kawamoto I Hata T Sekine A Uekusa H Ohashi Y 《Chemical & pharmaceutical bulletin》2002,50(12):1570-1573
The characterizations of the anhydrate (A-form), monohydrate (B1-form), and dihydrate (B2-form) of CS-834 were investigated by powder X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry-differential thermal analysis (TG-DTA), infrared spectroscopy, and Karl Fischer moisture titration. The typical DSC curve of the B2-form showed five endothermic peaks at 35.0, 46.4, 56.2, 99.2, and 190.4 degrees C and an exothermic peak at 123.4 degrees C. In TG-DTA analysis, the three peaks at 35.0, 46.4, and 56.2 degrees C had a total weight loss of 7.3%, corresponding to the release of two water molecules. From morphological observation under thermomicroscopy, the endothermic peak at 99.2 degrees C was attributed to the melting of the dehydrous crystals (B0-form) and the exothermic peak at 123.4 degrees C to the recrystallization to the A-form crystals. The endothermic peak at 190.4 degrees C was due to the melting of the A-form crystals. After incubation for 6.0 h at 35, 50, 60, and 80 degrees C, the powder X-ray diffraction patterns of the B2-form indicated that it was converted into the A-form via the B1-form and B0-form. Thus CS-834 exists in homologous hydrous crystal forms in multiple-phase transformations with the dehydration of two water molecules. 相似文献