Vibration testing based on impulse response excited by pulsed-laser ablation: Measurement of frequency response function with detection-free input

We have developed a non-contact vibration-measurement system that is based on impulse excitation by laser ablation (i.e. laser excitation) to measure the high-frequency-vibration characteristics of objects. The proposed method makes it possible to analyse the frequency response function just by measuring the output (acceleration response) of a test object excited by pulsed-laser ablation. This technique does not require detection of the input force. Firstly, using a rigid block, the pulsed-laser-ablation force is calibrated via Newton's second law. Secondly, an experiment is conducted in which an object whose natural frequency lies in the high-frequency domain is excited by pulsed-laser ablation. The complex frequency spectrum obtained by Fourier transform of the measured response is then divided by the estimated pulsed-laser-ablation force. Finally, because of the error involved in the trigger position of the response with respect to the impulse arrival time, the phase of the complex Fourier transform is modified by accounting for the response dead time. The result is the frequency response function of the object. The effectiveness of the proposed method is demonstrated by a vibration test of an aluminium block.     

Dynamical valence fluctuation at the charge-density-wave phase boundary in iodide-bridged Pt compound [Pt(chxn)2I]I2

We synthesized a novel iodo-bridged linear chain platinum compound, having the quasi-two-dimensional charge-density-wave (CDW) ground state and the smallest band gap. In this compound, we discovered an anomalous valence state in the boundary region at which the CDW phase alternates in the crystal by means of ESR, X-ray diffuse scattering, STM, and electrical resistivity. This anomalous state can be explained by the fast fluctuation between Pt(IV)-I...Pt(II) and Pt(II)...I-Pt(IV) in the double well potential. This is the first observation of the dynamical fluctuation of the CDW phase among the quasi one-dimensional halogen-bridged complexes.     

Gas Permeability of Poly (organophosphazenes)

Abstract

The gas permeability and an oxygen to nitrogen selectivity was determined with some poly (organophosphazenes). It is found from the data that the membrance having the highest gas permeability was [NP(NHPrⁿ) (NHEt)]_n, and had 1.5x10^?6 cm^3. cm/cm³ sec.cmHg to oxgen or 2.2x10^?6cm³.cm/cm³.sec.cm.Hg to nitrogen. On the other hand, the membrance having the highest oxgen to nitrogen selectivity of about 3, had the formular of [NP(OC₆H₄Cl-p)₂]_n. Also, the selectivity does not depend on the glass transition temperature of the membrances. The membrance prepared from [NP(OC₆H₄CH₃-p)₂]_n has a negative activation energy to oxgen and nitrogen permeability.     

Cyclotriphosphazatriene Derivatives. XXIX. Reaction of Cyclophosphazatriene Dichloride With Sodium Hydrosulfide

The chlorine substitution reaction of trimeric dichlorocyclophosphazene with sodium hydrosulfide has been examined. The reaction proceeded easily in dioxane and THF solutions. The reaction product, which had the chemical composition P₃N₃S₆H₆, was examined by ³¹P-NMR and IR spectroscopy. Further, it is suggested that the product was polymerized by heating with hydrogen sulfide, and the polymer (PNS) was formed.     

Phosphonitrilic Chloride. 40. Relationships between Electrical Conductivity and Thermal Behavior of Diaminotetraarylcyclotriphosphazenes

The behavior of various diaminotetraarylcyclotriphosphazenes N₃P₃(NH₂)₂R₄ on heating has been studied. The homocondensation reaction occurs with elimination of ammonia or aniline when the N₃P₃(NH₂)₂(OC₆H₅)₄, N₃P₃(NH₂)₂ (C₆H₅)₄, or N₃P₃ (NHC₅H₅)₆ is heated under various conditions. However, the homocondensation reaction does not proceed in case of N₃P₃ (NH₂)₂ (SC₆H₅)₄ because of the high conductivity of this compound.     

Online wide‐angle X‐ray diffraction/small‐angle X‐ray scattering measurements for the CO2‐laser‐heated drawing of poly(ethylene terephthalate) fiber

Fiber‐structure‐development in the poly(ethylene terephthalate) fiber drawing process was investigated with online measurements of wide‐angle and small‐angle X‐ray scattering with both a high‐luminance X‐ray source and a CO₂‐laser‐heated drawing system. The intensity profile of the transmitted X‐ray confirmed the location of the neck‐drawing point. The diffraction images had a time resolution of several milliseconds, and this still left much room for improvement. Crystal diffraction appeared in the wide‐angle X‐ray images almost instantaneously about 20 ms after necking, whereas a four‐point small‐angle X‐ray scattering pattern appeared immediately after necking. With the elapse of time after necking, the four‐point scattering pattern changed into a meridional two‐point shape. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1090–1099, 2005     

Anion- and cation-exchange MicroHPLC utilizing poly(methacrylates)-coated monolithic silica capillary columns.

A novel method was developed for the preparation of highly efficient anion- and cation-exchange microHPLC columns using an on-column polymerization of methacrylates having amine or sulfonic acid functional groups onto monolithic silica capillary columns modified with 3-methacryloxypropyltriethoxysilane as the anchor groups. The chromatographic evaluation of the columns using nucleic acids, nucleotides, and inorganic anions as samples showed the characteristics of the ion-exchange-type stationary phases. These columns exhibited higher separation efficiency when compared with the conventional particle-packed columns. A capillary column for the simultaneous anion- and cation-exchange separation could be prepared by a step-by-step functionalization. The advantages of this column preparation will include: (1) no need of column packing; (2) no need of the preparation of silane reagents possessing anion- and cation-exchange functionalities; (3) the amount of immobilized polymer could be controlled by changing polymerization conditions. These columns should be suitable for the separation of biologically active compounds by the microHPLC modes.