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1.
We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light. 相似文献
2.
3.
H. Yonezawa C. Yonezawa T. Shigematsu 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(1):125-134
Instrumental charged particle activation analysis (CPAA) for determining boron in a thin surface layer of silicon was developed. The nuclear reaction and incident energy were selected in order to minimize any interference from surface or bulk impurities. Thin boron film was used as a standard sample and its boron content was determined by neutron induced prompt -ray analysis. As a result, we were able to determine11B and10B at 1015 atoms/cm2 with an accuracy of better than 3% by 4 MeV proton and 7 MeV -bombardment, respectively. Each boron isotope could be determined down to 1013 atoms/cm2. Our CPAA was applied to determine boron in a boron implanted silicon wafer of a SIMS standard sample. 相似文献
4.
A study of the substoichiometric extraction of phosphorus is described. Phosphorus was extracted in the form of ternary compounds
such as ammonium phosphomolybdate, 8-hydroxyquinolinium phosphomolybdate, tetraphenylarsonium phosphomolybdate and tri-n-octylamine
phosphomolybdate. Consequently, phosphorus was extracted substoichiometrically by the addition of a substoichiometric amount
of molybdenum for all four phosphomolybdate compounds. On the other hand, phosphorus could be separated substoichiometrically
with a substoichiometric amount of tetraphenylarsonium chloride or tri-n-octylamine. Stoichiometric ratios of these ternary
compounds obtained substoichiometrically were 1∶12∶3 for phosphorus, molybdenum and organic reagent. Applicability of these
compounds to phosphorus determination was also discussed. 相似文献
5.
Phosphorus in orchard leaves (NBS SRM-1571) and spinach (SRM-1570) was determined by various substoichiometric analytical
methods such as the direct method, GRASHCHENKO's method and the method of carrier amount variation. All samples were labelled
with32P radioisotope. The data obtained by the method of carrier amount variation were also treated by the method of least squares
instead of De VOE's method. Phosphorus concentration in orchard leaves was 0.206±0.011% by the direct method, 0.219±0.011%
by GRASHCHENKO's method, 0.211±0.011% by the method of carrier amount variation and 0.207±0.007% by the method of least squares,
respectively. These values agree with the value reported by NBS (0.21±0.01%). Furthermore, these concentrations obtained by
various substoichiometric methods were compared with those by radioactivation reported in a prevoius paper. 相似文献
6.
Possibility of imide structure formation under microwave irradiation of molecules containing anhydride and isocyanate functional groups was investigated. The microwave-assisted polycondensation of aromatic diisocyanates and dianhydrides for preparation of polyimides was studied. The effect of microwave irradiation time and power, solvent nature, solid content of monomers, effect of catalyst, effect of polymerization reactor material and possibility of pressure development during polymerization, on the inherent viscosity of prepared polyimides were discussed. Experimental results showed that polymers obtained via this method had superior inherent viscosity and yield in comparison to the polymers obtained via conventional solution method. 相似文献
7.
T. Shigematsu M. Polasek H. Yonezawa 《Journal of Radioanalytical and Nuclear Chemistry》1996,203(1):3-9
In order to determine iron on silicon wafer surface at a level of 1014 atoms·m–2 the efficiency of a well-type Ge detector for59Fe -ray emissions was measured and a low temperature silicon direct bonding technique was developed. With silicon direct bonding at a temperature of 350 to 650°C iron remains near the interface of the bound silicon. The iron contamination of the interface escaped from the interface can be ignored with this technique. The value of iron obtained was (2.7 to 5.9)·1014 atoms · m–2 in the surface on silicon wafers. 相似文献
8.
On-line preconcentration system for the selective, sensitive and simultaneous determination of chromium species was investigated. Dual mini-columns containing chelating resin were utilized for the speciation and preconcentration of Cr(III) and Cr(VI) in water samples. In this system, Cr(III) was collected on first column packed with iminodiacetate resin. Cr(VI) in the effluent from the first column was reduced to Cr(III), which was collected on the second column packed with iminodiacetate resin. Hydroxyammonium chloride was examined as a potential reducing agent for Cr(VI) to Cr(III).The effects of pH, sample flow rate, column length, and interfering ions on the recoveries of Cr(III) were carefully studied. Five millilitres of a sample solution was introduced into the system. The collected species were then sequentially washed by 1 M ammonium acetate, eluted by 2 M nitric acid and measured by ICP-AES. The detection limit for Cr(III) and Cr(VI) was 0.08 and 0.15 μg l−1, respectively. The total analysis time was about 9.4 min.The developed method was successfully applied to the speciation of chromium in river, tap water and wastewater samples with satisfied results. 相似文献
9.
Y. Akishige H. Shigematsu T. Tojo H. Kawaji T. Atake 《Journal of Thermal Analysis and Calorimetry》2005,81(3):537-540
Summary Specific heats on the single crystals of Sr2Nb2O7, Sr2Ta2O7 and (Sr1-xBax)2Nb2O7 were measured in a wide temperature range of 2-600 K. Heat anomalies of a λ-type were observed at the incommensurate phase transition of TINC (=495 K) on Sr2Nb2O7 and at the super-lattice phase transition of TSL (=443 K) on Sr2Ta2O7; the transition enthalpies and the transition entropies were estimated. Furthermore, a small heat anomaly was observed at the low temperature ferroelectric phase transition of TLOW (=95 K) on Sr2Nb2O7. The transition temperature TLOW decreases with increasing Ba content x and it vanishes for samples of x>2%. 相似文献
10.
Successive band-splitting transitions occur in the one-dimensional map xi+1=g(xi),i=0, 1, 2,... withg(x)=x, (0 x 1/2) –x +, (1/2 <x 1) as the parameter is changed from 2 to 1. The transition point fromN (=2n) bands to 2Nbands is given by=(2)1/N (n=0, 1,2,...). The time-correlation function
i=xix0/(x0)2,xi xi–xi is studied in terms of the eigenvalues and eigenfunctions of the Frobenius-Perron operator of the map. It is shown that, near the transition point=2,
i–[(10–42)/17] i,0-[(102-8)/51]i,1 + [(7 + 42)/17](–1)ie–yi, where2(–2) is the damping constant and vanishes at=2, representing the critical slowing-down. This critical phenomenon is in strong contrast to the topologically invariant quantities, such as the Lyapunov exponent, which do not exhibit any anomaly at=2. The asymptotic expression for
i has been obtained by deriving an analytic form of
i for a sequence of which accumulates to 2 from the above. Near the transition point=(2)1/N, the damping constant of
i fori N is given by
N=2(N-2)/N. Numerical calculation is also carried out for arbitrary a and is shown to be consistent with the analytic results. 相似文献