A sinusoidal phase-modulating fiber-optic interferometer insensitive to the intensity change of the light source

In a conventional laser-diode sinusoidal phase-modulating (LD-SPM) interferometer, the wavelength of the LD is modulated by varying its injection current. The intensity modulation concurrent with the wavelength modulation leads to measurement errors. A photothermal-modulation method has been proposed to decrease the intensity change of the LD; however, this method cannot be used to measure vibration with a high frequency, and the beam diameter is too large to be used to measure minute objects. In this paper, we propose LD-SPM fiber-optic interferometer, in which the effect of the intensity change of the light source on measurement is eliminated. The diameter of the light beam is less than 0.5 mm. Using this interferometer, we measured displacements of a mirror driven by a piezoelectric transducer. The measurement repeatability is less than 1 nm.     

Single C59N molecule as a molecular rectifier

We report a new kind of experimental realization of a molecular rectifier, which is based on a single azafullerene C59N molecule in a double-barrier tunnel junction via the single electron tunneling effect. An obvious rectifying effect is observed. The positive onset voltage is about 0.5-0.7 V, while the negative onset voltage is about 1.6-1.8 V. Theoretical analyses show that the half-occupied molecular orbital of the C59N molecule and the asymmetric shift of the molecular Fermi level when the molecule is charged are responsible for the molecular rectification.     

Phase Diagram of RbI-SmI_2 Binary System and Structural Investigation of RbSm_2I_5 and RbSmI_3

The RbI-SmI2 , binary system was studied with DTA and X-ray powder diffraction. Its phase diagram shows that it has a congruently melting compound,RbSm2I5 , with a melting point 524℃; an incongru-ently melting compound, Rb2SmI4 , with an inconsruently point 467℃ and two compounds, RbSmI3, and Rb3SmI5, being decomposed at 433℃ and 460℃, respectively. The measured structure of RbSm2I5 shows that it is isomorphous with NH4 Pb2 Cl5 space group P21/c, a=10 . 063(3)A, b=9.003(3)A. c =14 . 242(5)A°,β=90.23(3)°;z = 4, MVx= 1 94 . 3cm3/mol;D=5.255g/cm3 and Do =5. 334g/cm3 (25. 0℃).The structural, investigation ofRbSmI3 shows that it belongs to the orthorhombic system with a = 15.914(6)A, b=8.898(3)A c =12.193(5)A; Z=8, MVx =130.0cm3/mol, Dx =4 . 743g/cm3,Do = 4.597g/cm3(25.0℃).     

Determination of miglitol in human plasma by liquid chromatography/tandem mass spectrometry

A rapid and sensitive method for the determination of miglitol in human plasma using voglibose as internal standard has been developed and validated. Samples of plasma were deproteinated with acetonitrile and washed with dichloromethane before being analyzed by reversed-phase high-performance liquid chromatography (HPLC). Separation was carried out on a short Nucleosil C(18) column (5 microm, 50 x 4.6 mm i.d.) using 10 mmol/L ammonium acetate at 1.0 mL/min as mobile phase. The detector was an Applied Biosystems Sciex API 4000 mass spectrometer using atmospheric pressure chemical ionization (APCI) for ion production. The instrument was operated at unit resolution in the multiple reaction monitoring mode. The assay was linear over the range 5.00-2000 ng/mL with a limit of detection of 1.00 ng/mL. Intra- and inter-day precision were <2.82% and <2.92%, respectively, with accuracy of 93.3-106%. The assay was successfully applied to a clinical pharmacokinetic study of miglitol given as a single oral dose (50 mg) to healthy volunteers.     

A study of the physiological changes and the nutritional qualities of irradiated apples and the effect of irradiation on apples stored at room temperature

The effects of γ-irradiation on the metabolism and nutritional qualities of cold Delicious apples and on the lethality of verticillate pathogenic fungi have been studied. The storage effect of irradiation on apples at room temperature has been observed. The results showed that the respiratory intensity of irradiated apple at 0.3–0.5 kGy was near or lower than that of unirradiated apple after 15 days irradiation. The amount of ethylene release was obviously inhibited when fruits were irradiated with 0.3–0.7 kGy. The flesh firmness of apple irradiated with 0.3–0.9 kGy was higher than that of unirradiated apple with the increasing of storage time. The negative correlations between the flesh firmness and the activities of pectinesterase (PE), polygalacturonase (PG) were observed when the dosage was lower than 1.5 kGy. The 2.0 kGy irradiation damaged the ultrastructure of cells, induced the softening of apple. When apples were irradiated with 0.7–2.0 kGy, the contents of 4 important volatile components of apple would be decreased. However, the dosage mentioned above had no effects on the pure chemicals. The studies showed that there was no significant effect of irradiation with 0.3–2.0 kGy on the nutritional qualities of apples and this dosage range could effectively control the verticillate pathogenic fungi. The result of storage experiments showed that the rotting fruits were obviously decreased by 0.3–0.9 kGy irradiation.     

Preconcentration of trace elements from natural water with palladium precipitation

Palladium salts can be used as a coprecipitation carrier for the preconcentration of trace elements from natural water prior to their measurement by atomic spectrometry (AAS). The palladium is subsequently reduced by the introduction of hydrogen gas into the sample solution. The procedure is applied to the determination of Cu, Pb and Cd in seawater (enrichment factor 50) and synthetic water samples. Operating conditions have been optimized for the analysis of real samples. With the technique established an enrichment factor (500 fold) is feasible in synthetic samples. The recoveries of Cu, Cd and Pb from seawater are 95, 103 and 100%, respectively. This simple and rapid method can be applied in a wide pH-range and with complex matrices.     

Preparation of multitracer solution from silver target irradiated by 80 MeV/nucleon 20Ne ions

A convenient procedure for preparing a multitracer solution from irradiated silver foils by 80 MeV/nucleon ²⁰Ne ions was developed. The carrier-free and salt-free solution containing 19 essential elements or trace elements for plant growth were prepared, and had been applied to study the regulation effect of metal ions on somatic embryogenesis of Lycium barbarum L.     

Self-assembly and UV-curing Property of Polymerized Lyotropic Liquid Crystal Monomer of Sodium 3,4,5-tris(11 acryloxyundecyloxy)benzoate

A polymerized lyotropic liquid crystal monomer of sodium 3,4,5-tris(11-acryloxyundecyloxy)-benzoate was synthesized by a convenient route starting from 3,4,5-trihydroxybenzoic acid via esterification followed by etherification, acylation and finally neutralization. The chemi-cal structure was confirmed by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance spectral analysis. The self-organization behavior of the monomer with deionized water in methanol at room temperature was also demonstrated. The assemblies were char-acterized by polarized optical microscope and X-ray diffraction. The results show that a solution containing 80:20 of the monomer to water was found to be able to self-organize into Lamellar (La) phase and 92:8 with inverted hexagonal (H_II) phase, which was in ac-cordance with the theoretical calculation of critical packing parameter. It suggests that the concentration of the monomer was the key factor to influence assembly structure. Addi-tionally, the acrylate conversion with different photoinitiators and nanostructure retention after polymerization were investigated. The research shows that the acrylate conversion of the monomer with Darocur2959 could reach up to 78% when irradiated by 30 mW/cm² UV light of 365 nm for 30 min characterized by Real-time FT-IR as well as the sol-gel method. Meanwhile, the La and H_II phase nanostructures were both retained after polymerization.     

Solubilization of boron nitride nanotubes

A successful attempt in the functionalization and solubilization of boron nitride nanotubes is reported, and a functionalization mechanism based on interactions of amino functional groups with nanotube surface borons is proposed.