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Densely arrayed (pitch 80 nm, were obtained using a chip with a laser section that is only 70 µm wide and 400 µm long.

In order to realize an efficient coupling between a flux-flow-type Josephson oscillator (FFO) and a stripline, we have carried out experiments to verify the mathematical model of the inductive coupling scheme between FFO and a stripline resonator in the frequency range between 50 GHz and 350 GHz. It is shown that the simulation using the proposed equivalent circuit for the inductive coupling scheme well explains the experimental results. The experimentally obtained center frequency and the bandwidth of the matching circuit were as large as 120 GHz and 40 GHz, respectively, which are also in reasonable agreement with those obtained in the simulation.

Experimental studies to enlarge kinetic inductance of NbN thin films using the effects of quality and thickness of the film are made by measuring Fiske current steps in the current-voltage (I-V) characteristics of NbN/Pb-In Josephson junctions. Experiments demonstrate that the specific kinetic inductance L K can be enlarged over a wide range by changing stoichiometry of the film, as well as by making the film thickness thin, and that this enlargement becomes larger by both effects when the film thickness is in an ultra thin regime. This inductance is shown to be well fitted to L K=µ0λ2/d, w h e r e µ_0 i s t h e v a c u u m p e r m e a b i l i t y, d i s t h e t h i c k n e s s, a n d λ i s t h e m a g n e t i c p e n e t r a t i o n d e p t h i n t h e d i r t y l i m i t. I n t h e p r e s e n t e x p e r i m e n t w e a t t a i n e d t h e i n d u c t a n c e a s h i g h a s L_K=130 p H b y t h e c o m b i n e d e f f e c t s o f i m p u r i t y a n d t h i c k n e s s f o r a f i l m w i t h d=30 n m.

A new type distributed reflector (DR) laser, which uses the multiquantum-well (MQW) waveguide as both the active and passive distributed reflector, is proposed and realised. Its superior lasing characteristics are experimentally confirmed by introducing Ga/sub x/In/sub 1-x/As-GaInAsP compressive strained MQW layers; the characteristics include a narrow linewidth of 743 kHz, high submode suppression-ratio (SMSR) of >41 dB at 2.2 times the threshold, and about two times larger differential quantum efficiency eta /sub df/ than that of DFB lasers. >

Mutant cats were developed with non-goitrous primary hypothyroidism. They were clinically characterized by severely retarded growth, mild anaemia and high mortality in the young. They responded markedly to thyroid hormone replacement. Thyroid glands in the mutants were normal in position but slightly reduced in size. Laboratory studies revealed low serum concentrations of thyroxine (T4) and tri-iodothyronine (T3), and increased serum concentrations of TSH. Administration of TRH induced no further increase in TSH. Administration of exogenous TSH after suppression of endogenous TSH by T3 did not increase the serum concentration of T4 in the mutants, in sharp contrast with the threefold increase in serum T4 observed in the normal litter-mates. These findings suggest that the underlying pathogenesis of this disorder is unresponsive to TSH. Moreover, we found that the mutants were transmitted in an autosomal recessive manner. Journal of Endocrinology (1991) 129, 245–251

For deuteron energies from 9.4 to 13.3 MeV the spectral neutron yield from a thick Be target bombarded by deuterons was determined by the use of time-of-flight techniques. Neutron energy spectra were measured between 0.4 and 18 MeV using a flight path of 12 m. For Ed = 13.3 MeV neutron energy spectra were determined at various angles of emission from 0 to 40 degrees. A pronounced peak at En = 0.8 MeV corresponds to the inelastic deuteron scattering on 9Be. The influence of neutron absorption and scattering on a water-cooled target was investigated and the experimental results were compared with calculations.

We propose a general form for the statistical bootstrap equation by means of a convolution formula for the thermodynamical system of hadronic matter. In connection with a phase transition of hadronic matter to a state of quark liberation, we predict the negative binomial distribution with k ∼1 for the multiplicity distributions in the central pseudorapidity region at high energies.

Substoichiometric isotope dilution analysis has been applied for the determination of trace elements in liquid samples, of carrier content in radioisotope solution and of concentration of organic reagent. Cu in mineral acids and in ZnSe single crystal was determined by the substoichiometric extraction with dithizone. The values of 1.8 and 0.018 ppm in nitric acid and distilled one and of 1.4 and 0.44 ppm in ZnSe were obtained. Cu and P carrier contents in64Cu and32P solutions were determined by the substoichiometric extractions with dithizone in CCl4 and with molybdic acid into MIBK in the series of the solutions adding various amounts of Cu or P carrier. An analogous method has been applied for the determination of dithizone and diethyldithiocarbamate solutions. The method was also applied for the determination of60Co radioactivity in environmental samples. The analytical result of water samples is described.

An analytical method for the simultaneous determination of rare earth elements by using substoichiometry with two chelating agents, a complexon and an extracting agent, is proposed. The principle of the method is that the element which has the lowest stability constant with the complexon is separated substoichiometrically, while other elements which have higher stability constants are separated quantitatively by a single extraction. This method was applied to neutron activation analysis of rare earth elements. Lanthanum, europium and terbium in orchard leaves were determined simultaneously by using substoichiometric separation with DTPA and TTA.

Uranium and thorium in LSI materials were determined by INAA and α-particles in these materials were also measured. The contents of uranium and thorium and the α-activity in ceramics and zirconia samples were very high. Calculation of α-flux from uranium and thorium contents and analysis of α-spectra were carried out for the ceramics and zirconia samples. The calculated values of α-flux in these samples agreed with the α-flux measured.

The stress corrosion cracking (SCC) of AISI 304 and AISI 316 austenitic stainless steels in 0.82 kmol/m3 HCl and H2SO4 solutions has been investigated as functions of stress and solution t...

The paper deseribes the determination of indium in metallic tin and cadmium metals by the direct method, which is a variant of substoichiometric radioactivation analysis. It is based on substoichiometric extraction of indium diethyldithiocarbamate into carbon tetrachloride. Indium in tin metal was determined by116mIn (T=54 min), while115mIn (T=4.5 h), formed by the reaction114Cd(n, γ)115Cd was used for cadmium samples. The irradiated sample was dissolved and the radioactivity of116mIn or115mIn, A, was measured. After the separation of indium from the matrix, a known amount of indium, m, was separated substoichiometrically and the radioactivity, a, was measured. Indium was calculated as Mx=m A/a. If a known amount of the element, M, is added to the irradiated sample in advance, the equation for calculation is given as Mx-m A/a−M. By this method, indium can be determined without any consideration of self-shielding and secondary nuclear reaction of the matrix.

The electrical properties of 10 BP wafers grown by chemical vapour deposition at room temperature before and after irradiation by thermal neutrons were measured by the van der Pauw method. No appreciable change in electrical properties was observed for the (100) wafer. In the case of the (111) wafer, the carrier concentration for the n type increased and decreased for the p type after irradiation with thermal neutrons owing to the formation of donors caused by nuclear reaction of 10 B(n,α) 7 Li. The electrical conductivity σ, the carrier concentration n and the mobility μ of the (111) wafer after irradiation were measured at high temperatures: n decreased and μ increased for the p type (and vice versa for the n type) compared with the values before irradiation. The temperature dependence of carrier concentration before and after irradiation was correlated with the theoretical curves to calculate the donor and acceptor concentrations and their activation energies.

Ellipsometric and electrochemical measurements of the anodic passivation and secondary passivation films on nickel in borate buffer solution at pH 8·42 were made. The reference bare surface, obtained by cathodic reduction of electropolished nickel, gives the optical constants N 3 = 1·65−3·81 i for nickel. In the passivity region, where a little dissolution of nickel occurs, the surface film has the optical constants N 2 = 2·7−0·25 i and the film thickness as estimated by ellipsometry increases linearly with rise of the potential, from 4 to 13 A, which is in fairly good agreement with the coulometrically estimated film thickness. In the oxygen evolution region, secondary passivation occurs with an abrupt increase in both optical constants and thickness of the surface film. The anodic passivation of nickel is compared with that of iron in terms of thickness of the surface film as a function of potential.

A method of radioactivation analysis has been developed for the determination of chromium. It is based on the substoichiometric extraction of chromium diethyldithio-carbamate into methyl-isobutyl-ketone from acetate buffer solution in the presence of EDTA and potassium cyanide. The method has been applied for the determination of chromium in high-purity calcium carbonate and NBS glasses as standard reference materials.

The results of this study demonstrated that the i.v. administration of insulin, in the form of a conjugate with either syngeneic spleen cells (SC) or peritoneal exudate cells (PEC), markedly reduced the capacity of recipient mice to develop insulin-specific immune responses, as manifested by diminished in vivo IgE antibody production and by depressed in vitro, lymph node cell proliferation responses, respectively. Furthermore, it was shown that i.v. injection of insulin-PEC conjugates induced the activation of suppressor cells that had the capacity to downregulate insulin-specific IgG plaque-forming cell (PFC) responses. Finally, it was also determined that freezing and thawing of the insulin-PEC conjugates resulted in the release of a soluble tolerogenic molecule and/or membrane preparation that could also markedly depress insulin-specific IgG antibody production.

Charged multiplicity distributions obtained in pp collisions at s =540 GeV for various pseudorapidity intervals are investigated using the cluster model. It is shown that the observed pseudorapidity dependence of these distributions are well described by a simple three-cluster model. The leading-particle effect is also estimated in this model.

To assess the physiological role of atrial natriuretic factors in the regulation of blood pressure and sodium-water excretion, we studied the chronic effects of continuous infusion of a synthetic atrial natriuretic factor of 25 amino acids for up to 3 days on systolic blood pressure, urine volume, and urinary excretion of sodium, prostaglandin E2 and kallikrein in conscious rats, and also evaluated the antihypertensive effect of this substance in rats with hypertension caused by chronic infusion of norepinephrine. Continuous infusion of atrial natriuretic factor (150 micrograms/kg per day) into the jugular vein via osmotic minipumps did not induce any changes in systolic blood pressure, urine volume, and urinary excretion of sodium, prostaglandin E2, and kallikrein for up to 3 days, compared with those in vehicle-infused rats. When the same dose of atrial natriuretic factor was administered simultaneously with 1.8 mg/kg per day of norepinephrine infused intraperitoneally by osmotic minipumps, the systolic blood pressure of conscious rats rose on day 1 to only 127.3 +/- 6.3 mm Hg compared with the rise to 146.3 +/- 1.6 mm Hg when norepinephrine alone was infused (P less than 0.05). The antihypertensive effect of atrial natriuretic factor was sustained for 3 days in rats infused with norepinephrine. The administration of atrial natriuretic factor to rats made hypertensive by 3 days of infusion with norepinephrine alone returned the blood pressure to control levels, and the antihypertensive effect was sustained throughout the experimental period lasting for 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)

This paper describes the effect of solution pH on the passive film on iron which was investigated by ellipsometry and by cathodic reduction combined with chemical analysis. Anodic two-step passivation was employed to exclude anodic deposition of ferrous ion, resulting from anodic oxidation of iron. The film in acid solution is almost anhydrous oxide, whereas the film in neutral and alkaline solution has an outer hydrated oxide layer, whose thickness decreases with decreasing pH. The hydrated outer layer depends also on the anion present in solution. The transition layer model of the film is proposed to explain the results.

We examined in vitro the inhibitory effects of ovomacroglobulin on collagenolytic activity in Bacteroides gingivalis (B. gingivalis) culture supernatant, in human peripheral blood polymorphonuclear leucocytes (PMN), and in gingival crevicular fluid (GCF) from periodontitis patients. Measurement of collagenolytic activity was conducted with a CollagenoKit CLN-100 using FITC-conjugated type I collagen. The FITC-conjugated collagen was reacted with the sample in solution, and the residue was selectively degenerated at 35 degrees C and removed with ethanol. The fluorescence of the removed residue was then measured. The collagenolytic activity from B. gingivalis displayed dose dependent inhibition as high as 81.4% following addition of ovomacroglobulin at 224 micrograms/ml. The collagenolytic activity from human peripheral blood PMN showed, as a result of addition of 1,600 micrograms/ml of ovomacroglobulin, inhibition as high as 62.4%. The collagenolytic activity from human GCF, which was obtained from patients with different degrees of periodontal disease, exhibited as high as 71.0% inhibition after addition of 1,600 micrograms/ml ovomacroglobulin. Ovomacroglobulin showed almost the same level of inhibition obtained from alpha 2-macroglobulin, which was measured as a positive control. It was also recognized by SDS-PAGE that collagenolytic activity was inhibited after preincubation with added ovomacroglobulin. This collagenolytic activity, which dissolved the collagen substrate, was derived from B. gingivalis and human GCF. The above results demonstrate that ovomacroglobulin inhibits collagenolytic activity from B. gingivalis, human PMN, and human GCF.

Oxygen in silicon was determined by the secondary nuclear reactions of6Li(n, α)T and16O(t, n)18F. Lithium fluoride was deposited in vacuum on fused quartz, covered with the sample and irradiated in a nuclear reactor. The depth profiles of18F in fused quartz and in silicon were observed, and enough depth to eliminate surface oxygen was estimated. On the basis of these results, oxygen was determined by the average cross-section method. Oxygen concentration in CZ silicon with various growing condition was 5–26 ppm and was consistent with those determined by the infrared absorption method. The detection limit of oxygen in silicon is 5 ppm.

Ionic packing factors defined as the ratio of the cation radius to the radius of its anion interstice are calculated for cations of the normal 2–3 spinels. Distinct relationships are found between ionic packing of the 8a site and electric conductivity, and between ionic packing of the 16d site and magnetic ordering of ions in the 16d site.

A two-temperature model is proposed for the semi-inclusive transverse momentum (p T ) distributions at the CERN $$p\bar p$$ collider. Our model accounts well characteristic multiplicity dependence of thep T distributions. Energy dependence of thep T distributions is investigated in comparison with the data at ISR energies. High temperature state becomes more important at high energy and multiplicity regions. The ratio between high and normal temperature is almost independent of energy and multiplicity.

The paper describes a method of radioactivation analysis for the determination of indium, copper and nickel. In the determination of indium, ordinary and displacement substoichiometries were applied for glassmaking materials while ordinary substoichiometry was applied for NBS standard reference materials. Copper and nickel in glassmaking materials and NBS standard reference materials were also determined by the displacement and ordinary substoichiometries. Indium contents in glassmaking materials by the two methods agreed with each other. The analytical results of indium, copper and nickel in NBS' SRM were also in good agreement with published values and certified values by NBS.

The single comparator method in neutron activation analysis has been applied to the investigation of the purity of silicon single-crystals of different origins. The following impurities were determined: Au, Sb, Co, Cu and Na. Studies were also carried out on the surface contamination of silicon samples introduced through steps of sample preparation and irradiation. Up to nineteen elements on the surface of samples were analysed and found to be easily reduced to low levels or detection limits by washing and etching.

We demonstrate new scaling behavior of the ratio of mean transverse momenta between in inclusive and semi-inclusive reactions. This scaling property is derived from KNO (Koba, Nielsen and Olesen) scaling and SIM (scaling in the mean). New data, which contain the jet-event sample, observed by the recent collider experiments support our proposal.

Magnetic moments, magnetic susceptibilities and optical absorption of the system Hg x Zn 1- x Cr 2 Se 4 have been measured. A correlation is found between the optical and the magnetic properties.

A method of radioactivation analysis has been developed for the substoichiometric determination of cobalt, copper and manganese in glass and glass-making materials. The substoichiometric extraction of cobalt with α-nitroso-β-naphthol was studied and simple procedures are suggested for the determination of the three elements. Cobalt is extracted substoichiometrically as α-nitroso-β-naphtholate into chloroform from solution of pH 6.2, copper as dithizonate in carbon tetrachloride from weak acidic solution, and manganese as tetraphenylarsonium permanganate into chloroform after oxidation to permanganate. Contents from 2 ppm to 3 ppb of cobalt, copper and managanese were analysed in glass-making materials, and it is shown that the method for their determination is reliable and superior in accuracy and reproducibility.

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.

The substoichiometric precipitation of fluoride with lanthanum was studied by using18F and140La tracers and it was found that fluoride could be precipitated substoichiometrically with lanthanum and the reaction ratio between fluoride and lanthanum was 3∶1. The pH range at which fluoride can be separated substoichiometrically with lanthanum is between 2 and 8. Barium and indium interfere in the precipitation of fluoride, sodium, copper and manganese, however, not. Fluorosilicate can also be precipitated substoichiometrically by using lanthanum as a precipitant and the reaction ratio between fluorosilicate and lanthanum was 1∶2. This separation was applied for the determination of oxygen in silicon crystals. The concentration of oxygen measured in some silicon crystals was between 5 and 27 ppm and in good agreement with those by non-destructive method and infrared spectrophotometry.

A substance capable of promoting tumour cell aggregation was released from rat ascites hepatoma cell (possibly from the cell surface) kept in Hanks' balanced salt solution (free of calcium and magnesium) in the cold, and then partially purified by chromatography with DEAE-Sephadex and gel filtration with Bio-gel. The thermostable substance seemed to be a glycoprotein and its molecular weight was about 72,000 when measured by gel filtration on Sephadex G-200. It had no proteolytic activity. The material was clearly effective for rat ascites hepatoma cells as well as SV40 transformed cells, but less effective for Chang's cells and apparently ineffective for normal rat liver cells and red blood cells. The action of this material was more potent than that of Jack bean concanavalin A when assayed for aggregation of SV40 transformed cells. Its effect was not influenced by concanavalin A inhibitors such as alpha-methyl-D-glucopyranoside, N-acetyl-D-glucosamine and D-glucose. ImagesFig. 1Fig. 2Fig. 3

Contamination sources of trace elements introduced into silicon crystals grown by the Czochralski technique are investigated: the signale comparator method in neutron activation analysis is applied to the determination of impurities in a silica crucible polycrystalline silicon, grown crystals and residual melt. When particular care is taken to avoid contamination during crystal growth, it is possible to obtain high purity silicon crystals in which impurity contents are almost below the detection limits of the analytical method.

A method of radioactivation analysis has been developed for the determination of 17 elements as impurities in high-purity optical glasses. The substoichiometric extraction of platinum with dithizone was studied and a simple procedure was proposed for the determination of platinum. Copper and manganese were also determined substoichiometrically by the extractions with dithizone and with thenoyltrifluoracetone, respectively. The non-destructive γ-ray spectrometry using a Ge(Li) detector has been applied for the determination of the other 14 elements (Ag, Co, Cr, Eu, Fe, Ir, Sc, Zn, Cs, Hf, Rb, Sb, Ta and Tb). Impurity elements at the ppb level were analysed by the proposed method and it is shown that the method is reliable for the determination of trace impurities in high-purity optical glasses.

In view of the scaling-in-the-mean hypothesis we propose a method to derive the relation between the momentum distributions in inclusive and semi-inclusive reactions. Our formula is useful to make a discrimination among the similar p/sub T/ distribution functions. We predict that the inclusive p/sub L/ distribution function in terms of p/sub L// shows energy dependence, comparing the Koba-Nielsen-Olesen scaling hypothesis and the two-component model for the multiplicity distributions.

5 alpha-Cholest-8(14)-en-3 beta-ol-15-one is a potent inhibitor of cholesterol biosynthesis which has significant hypocholesterolemic activity upon oral administration to animals. Described herein are the results of experiments that indicate the presence of the 15-ketosterol in rat skin. The 15-ketosterol was, after purification by medium pressure liquid chromatography on Lichroprep RP-8 columns, thin-layer chromatography on silica gel G, and reverse phase high performance liquid chromatography, characterized by gas-liquid chromatography-mass spectrometry in the form of its trimethylsilyl ether derivative. The use of an internal standard containing both tritium and deuterium permitted the determination of the levels of the 15-ketosterol by mass fragmentography. The results of five separate analyses of portions of the skin of a male Sprague Dawley rat showed a mean value of 84.5 +/- 4.1 (SEM) ng per g. Analyses of hair samples of ten male Sprague Dawley rats indicated a mean level of 143 +/- 19 (SEM) ng per g of hair. Most (approximately 72%) of the 15-ketosterol in hair was esterified. This report constitutes the first isolation of the 15-ketosterol from animal tissues.

The direct breakdown voltage was measured for a needle-plane electrode system in silicone oil, with polymer films of polypropylene, polyethylene terephthalate, fluorinated ethylene propylene, and polyamide on the plane. In the silicone oil alone, the breakdown voltage increased with increasing gap distance for both polarities, the values being highest with the needle negative. In the silicone oil/polymer film composite, with the needle positive, the breakdown voltage was higher than for the oil alone. Although breakdown initiated at the needle tip, the polymer film acted as a barrier to increase the system breakdown voltage. However, with the needle negative the breakdown voltages of all the composite systems, with exception of the polyamide film, were lower than for the oil alone. This is attributed to negative ions deposited on the film which create a high field and initiate breakdown in the film.

A new fast neutron spectrometer has been developed. The spectrometer is consisted of a thin recoil proton radiator in close contact to a single wafer dE-E Si detector, in which an epitaxial dE counter of less than 0.01 mm and a thick E counter are incorporated. Proton recoil angle and the energy can be computed from the dE and E counter outputs in each recoil event, thus an unfolded neutron spectrum can be attained. The basic characteristics, computer simulation work and experimental results for monochromatic neutrons are described.

A review of the substoichiometry in trace analysis is presented. The principle of the method, practical applications and recent developments are described.

Substoichiometric extraction of chromium with tetraphenylarsonium chloride (TPACl), tri-n-octylamine (TNOA), diethylammonium diethyldithiocarbamate (DDDC) and ammonium pyrrolidinedithiocarbamate (APDC) was examined in detail. Chromium can be extracted substoichiometrically in a pH range, which is 1.1–2.6 for the TPACl compound, 0.6–2.3 for the TNOA compound, 5.1–6.4 for the DDCC chelate and 3.9–4.9 for the APDC chelate. Chromium in high-purity calcium carbonate, Orchard Leaves (NBS SRM-1571) and Brewers Yeast (NBS SRM-1569) was determined by neutron activation analysis combined with substoichiometric extraction by DDDC and APDC. The values of 2.0±0.02 ppm and 2.6±0.2 ppm were obtained for Brewers Yeast and Orchard Leaves, respectively. These values were in good agreement with the values reported by NBS. The reaction mechanism and the reaction ratio between hexavalent chromium and dithiocarbamate were also discussed.

Trace amounts of transition elements (Co, Cr, Cu, Fe, Mn and V) and other seven elements in optical waveguide samples were determined by INAA. The contents of impurities in ultra-pure materials are less than those of high-purity materials and of G.R. grade. The increase of contamination of trace transition elements and iridium from furnace or crucible are observed in the production of optical glass fibers. Up to seventeen elements were determined in five NBS biological standard reference materials: Oyster Tissue: SRM-1566, Brewers Yeast: SRM-1569, Spinach: SRM-1570, Orchard Leaves: SRM-1571 and Tuna Fish, and in four Japanese biological standard reference materials: Tea Leaves B&C, Pepperbush and Shark Meat. The analytical results in NBS and Japanese standard reference materials are in good agreement with published values and certified values by NBS.

The determination of trace elements in highly activated matrix components was carried out by neutron activation analysis using the radioisotope addition technique. The method is based on the addition to the irradiated test sample of a radioisotope which is a diffeent nuclide of the element to be determined. After separation, the chemical yield is calculated from the radioactivity added and the element is determined by an ordinary technique. Twelve elements in indium phosphide and eight elements in gallium arsenide could be determined by the method.

The substoichiometric separation of lanthanum was studied on the system EDTA —lanthanum—8-hydroxyquinoline. The optimum conditions for the substoichiometric separation of lanthanum were calculated theoretically and these results were examined experimentally. By using the two chelating agents, EDTA and 8-hydroxyquinoline, lanthanum could be separated substoichiometrically with good accuracy and precision. This method was applied to the determination of lanthanum by activation analysis, and found to be available for the determination of trace amount of lanthanum.

A method of rapid determination for indium, nickel and copper in Spinach (NBS; SRM-1570) by substoichiometric radioactivation analysis is described. The method is based on the principle that an equal amount of non-irradiated test sample is added to the irradiated standard sample and subsequent substoichiometric extraction for the irradiated test and standard samples is carried out. Indium is extracted as diethyldithiocarbamate into carbon tetrachloride, nickel as dimethylglyoximate into chloroform and copper as dithizonate into carbon tetrachloride. The radioactivities of these extracts are measured by NaI(Tl) or Ge(Li) detector coupled with pulse-height analyser. The analytical results obtained by the method were in good agreement with our published values and certified values by NBS.

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.

The separation of fluorine was studied by several inorganic ion exchangers. A high yield of adsorption for fluorine was obtained using hydrated tin dioxide in 1N nitric acid. Fluorosilicate can be separated under the same conditions. It was also found that fluorine and fluorosilicate could be separated substoichiometrically. The substoichiometric separation was applied to the determination of oxygen in silicon crystals by radioactivation analysis. The concentration of oxygen was 28 ppm and agreed with that from a non-destructive method.

Three analytical methods for uranium by neutron activation are described. The methods are based on the substoichiometric separation of barium or lanthanum, which are the fission products of uranium-235 by neutron irradiation. Uranium contents in high purity materials were determined by the methods, which were found to be useful for the determination of a trace amounts of uranium.

Determination of fluorine adsorbed on inorganic ion exchanger was studied by activation analysis using 19F(γ,n)18F and 19F(n, α)16N reactions. Hydrated tin dioxide and activated alumina were used as inorganic ion exchangers. After adsorption of fluorine on the column, the exchanger was irradiated by the linear electron accelerator and 252Cf fission neutron source, and the content of fluorine was determined by reactivation. The determination of oxygen in silicon single crystal was studied by the reactivation analysis.