Sample records for radionuklidov drevesnymi rasteniyami
-
Energy Technology Data Exchange (ETDEWEB)
Hiyama, Yoshio [University of Tokyo (Japan)
1960-07-01
sobre el analisis quimico de las aguas marinas y del cuerpo humano, trata; de encontrar una relacion entre el grado de contaminacion del agua del mar por varios radionuclidos y el grado de intensidad de la dosis de radiacion en el cuerpo humano causada por estos radionuclidos de origen marino. Sin, embargo, aunque los especialistas en oceanografia, salud publica, nutricion, radiobiologia y en otras materias reconozcan la conveniencia de efectuar; esos calculos habra que obtener mas datos sobre la cantidad de trazadores, en las aguas del mar, en los productos marinos y en el cuerpo humano, para confeccionar un cuadro de las concentraciones maximas admisibles de diversos radionuclidos en las aguas del mar. En la memoria, el autor se limita a enunciar la idea y a describir algunos ejemplos. (author) [Russian] V nastojashhem doklade avtor stremitsja najti svjaz' mezhdu urovnem zarazhennosti morskoj vody nekotorymi vidami radionuklidov i urovnem radiacionnoj dozy, poluchaemoj chelovekom v rezul'tate dejstvija radionuklidov morskogo proishozhdenija; avtor ispol'zuet pri jetom rekomendacii MKRZ i nekotorye dannye himicheskogo analiza morskoj vody i chelovecheskogo organizma, izvestnye emu. Odanko, esli ideja jetih raschetov budet priznana uchenymi v oblasti okeanografii, zdravoohranenija, pitanija, radiacionnoj biologii i dr., vse zhe potrebujutsja dopolnitel'nye dannye o kolichestvah metjashhih jelementov v morskoj vode, v produktah morja i v chelovecheskom organizme dlja togo, chtoby zavershit' tablicu maksimal'no dopustimyh koncentracij v morskoj vode razlichnyh vidov radionuklidov. Ideja, vyskazannaja v doklade, nosit chisto predvaritel'nyj harakter; v doklade takzhe dajutsja nekotorye primery. (author)
-
Energy Technology Data Exchange (ETDEWEB)
Ophel, I. L. [Environmental Research and Radiation Dosimetry Branch, Division of Biology and Health Physics, Atomic Energy of Canada Limited, Chalk River, ON (Canada)
1960-07-01
otnoshenijah jeta reka predstavljaet ozero. Jeffljujent razbavljaetsja bol'shimi ob{sup e}mami nizkoaktivnoj vody, ispol'zovannoj dlja ohlazhdenija, i postupaet v reku pri koncentracii radionuklidov, ne prevyshajushhih predel'no dopustimoj koncentracii dlja rabochih. Obshhaja koncentracija beta- i gamma-radionuklidov vverh po techeniju ot zavoda sostavljaet 2 x 10{sup -8} millikjuri/millilitr i 1,6 kilometra vniz po techeniju ot zavoda ravna 3 x 10{sup -8} millikjuri/millilitr. Vzjatie prob so dna reki pokazyvaet, chto radioaktivnost' ponizhaetsja v techenie celogo rjada let nesmotrja na postojannoe dobavlenie aktivnosti, osazhdajushhejsja na kolloidal'nom kremnii, vydeljajushhemsja iz vody. Iz rechnyh organizmov chelovekom upotrebljaetsja v pishhu tol'ko krupnaja ryba. Sledy stroncija-90 byli sluchajno obnaruzheny v kostjah, no ne v mjase. Maksimal'noe soderzhanie 10{sup -3} millikjuri R{sup 32}/g obshhego vesa bylo obnaruzheno v nebol'shih okunjah. Hotja fosfor-32 sostavljaet tol'ko 0,04% obshhej radioaktivnosti jeffljuenta, on predstavljaet 75-95% vseh radionuklidov obnaruzhennyh v bol'shinstve vzjatyh na issledovanie ryb. (author)
-
Energy Technology Data Exchange (ETDEWEB)
Dvorska, L; Dulanska, S [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra jadrovej chemie, 84215 Bratislava (Slovakia)
2012-04-25
An important and fundamental fact in the operation of nuclear power plants is that there is no production of greenhouse gases and pollutant emissions especially nitrogen oxides NO{sub x}, carbon oxides CO and CO{sub 2}, sulfur dioxide and fly ash. Alpha radionuclides in fly ash from thermal power Novaky {sup 238}U, {sup 234}U, {sup 235}U, {sup 239,240} Pu, {sup 238}Pu and {sup 241}Am were separated on extraction-chromatographic sorbents TRU Resin and Resin UTEVA involved in the vacuum box in tandem. Samples for the measurement of alpha radionuclides were measured on a double-chamber 576A spectrometer with ULTRA Alpha Detector 600, EG and G ORTEC. There was not detected any increased activity value of uranium isotopes comparing the activity of {sup 238}U and {sup 234}U with the Slovakian Collection of Laws 345/2006. (authors)
-
Czech Academy of Sciences Publication Activity Database
Kulko, A. A.; Skobelev, N. K.; Burjan, Václav; Hons, Zdeněk; Daniel, A.V.; Demekhina, R.; Kalpakchieva, R.; Kugler, Andrej; Mrázek, Jaromír; Penionzhkevich, Y. E.; Piskoř, Štěpán; Sobolev, Yu. G.; Šimečková, Eva
2011-01-01
Roč. 75, č. 4 (2011), s. 574-576 ISSN 0367-6765 R&D Projects: GA ČR GAP203/10/0310; GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : excitation functions * cross sections * radioactive beams Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
-
Energy Technology Data Exchange (ETDEWEB)
Gyrbuchev, I.; Dinchev, D. [Institut Pochvovedenija Im.N. Pushkarova, Sofija (Bulgaria)
1968-07-01
Some forty years ago Mattson attempted to represent soil solutions as ionic states. Later on, he further developed his theory with the aid of the latest achievements in physical chemistry. In 1955 Schoffield applied chemical thermodynamics to make the interrelations between the solid and liquid phases of the soil even more precise. Nitrogen occupies a special position among the plant nutrients. The greatest success in nitrogen uptake and metabolism studies, however, has been achieved only recently after the development of isotope techniques. The study of nitrogen metabolism using isotope techniques has been carried out for some years at the N. Poushkarov Institute of Soil Science using optical methods of isotope detection. Certain of the results obtained recently point to the great opportunities offered by the use of the optical method. Greenhouse and field experiments were carried out with wheat, oats and lucerne. Ammonium sulphate with 11.50 at.%, {sup 15}N,andurea 5.55 at % were used as sources of nitrogen. Depending on the conditions, the nitrogen introduced with fertilizers was utilized by the plants in amounts ranging from 47 to 56% in the greenhouses, and from 38 to 45% m the field. It was established that the soil was the source of nearly half the nitrogen of the plants. Fertilized plants took up more of the soil nitrogen than the unfertilized plants. The nitrogen introduced into the soil was found in all fractions of the plants after 24 h and was in the non-protein organic nitrogen, constitution proteins, chlorophyll and reserve proteins of the plants. The highest amounts of {sup 15}N were found in the following free amino acids: arginine, histidine, lysine and the amide aspargine. In the bound amino acids, alanine, threonine, serine and glycine were highest in {sup 15}N. Phosphorus application increased the amounts of nitrogen in the amino acids. It was established that nitrogen turnover was greatest in chlorophyll and the constitution proteins. In the study of the quality of wheat grains, it has been shown that the highest amounts of nitrogen were found in the glutenins, followed by the fractions of residual nitrogen, prolamins and the water-soluble nitrogen compounds. The least amounts were found in the albumins and globulins. (author) [Russian] 40 let nazad Mattson pytalsja predstavit' pochvennye rastvory kak ionnye sostojanija. Pozdnee on razvil svoju teoriju, osnovyvajas' na poslednih dostizhenijah v oblasti fizicheskoj himii. V 1955 godu Shhoffild primenil himicheskuju termodinamiku dlja togo, chtoby eshhe bol'she utochnit' vzaimootnoshenija mezhdu tverdymi i zhidkimi fazami pochvy. Azot zanimaet osoboe mesto sredi pitatel'nyh veshhestv rastenij. Odnako naibol'shij uspeh v issledovanijah azotistogo pogloshhenija i metabolizma byl dostignut lish' nedavno posle razrabotki izotopnyh metodov. Issledovanie azotistogo metabolizma s pomoshh'ju izotopnyh metodov provodilos' v techenie neskol'kih let v Institute pochvovedenija im. N.Pushkarova s ispol'zovaniem opticheskih metodov obnaruzhenija izotopov. Nekotorye iz poluchennyh nedavno rezul'tatov ukazyvajut na ogromnye vozmozhnosti, kotorye otkryvajutsja v rezul'tate ispol'zovanija opticheskogo metoda. Jeksperimenty v teplichnyh i polevyh uslovijah provodilis' na pshenice, ovse i ljucerne. V kachestve istochnikov azota ispol'zovalis' sul'fat ammonija s 11,50 i mochevina s 5,55 atomnyh procentov {sup 15}N. V zavisimosti ot uslovij azot, vvodimyj s udobrenijami, ispol'zovalsja rastenijami v kolichestve ot 47 do 56% v teplicah i ot 38 do 45% - v polevyh uslovijah. Ustanovleno, chto pochva javljalas' istochnikom pochti poloviny azota v rastenijah. Udobrennye rastenija pogloshhali bol'she pochvennogo azota, chem neudobrennye. Azot, vvedennyj v pochvu, byl obnaruzhen vo vseh frakcijah rastenij spustja 24 chasa i soderzhalsja v nebelkovom organicheskom azote, konstitutivnyh belkah, hlorofille i rezervnyh belkah rastenij. Naibol'shee kolichestvo 15N bylo obnaruzheno v sledujushhih svobodnyh aminokislotah: arginine, gistidine, lizine i amidoasparagine. V svjazannyh aminokislotah - alanine, treonine, serine i glicine - soderzhalos' naibol'shee kolichestvo 15N. Primenenie fosfora uvelichivalo kolichestvo azota v aminokislotah. Ustanovleno, chto oborot azota byl samym bol'shim v hlorofille i konstitutivnyh belkah. Pri issledovanii kachestva pshenichnyh zeren bylo ustanovleno, chto naibol'shee kolichestvo azota bylo obnaruzheno v gljutenine, zatem vo frakcijah ostatochnogo azota, prolamina i vodorastvorimyh azotnyh soedinenijah. Naimen'shee kolichestvo bylo obnaruzheno v albumine i globuline.
-
Energy Technology Data Exchange (ETDEWEB)
Dzhepo, S P; Skal` skij, A S; Bugaj, D A; Gudzenko, V V; Mogil` nyj, S A; Proskura, N I [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Geologicheskikh Nauk; [Admyinyistratsyiya zoni vyidchuzhennya, Chernobil` (Ukraine)
1994-12-31
Experimental investigations carried out on testing grounds have permitted studying hydrogeological and geochemical conditions, contamination levels of ground waters and mechanisms of radionuclide migration in the areas of radioactive waste burial in sector 2.1 of temporary area for radioactive waste localization << Ryzhy Les >>. Distribution coefficients for {sup 137} Cs and {sup 90} Sr as well as chemical forms of sorbed radionuclides have been determined under in situ conditions. Lateral rates of radionuclide migration in ground waters are estimated.
-
Directory of Open Access Journals (Sweden)
Grigoryev Andrey
2011-01-01
Full Text Available This paper focuses on the impact of certain factors on the contemporary distribution of natural (226Ra, 232Th, 40К and anthropogenic (137Cs, 60Co radionuclides in the sediments of the Baltic Sea. The results of the study suggest that the distribution of 137Cs is determined by the content of hydromica of silty-clay and clay grain-size fractions, while radiocaesium is mainly accumulated by silty fractions. The accumulation of 226Ra by bottom sediments is mainly determined by the pH geochemical barrier at the water-seafloor boundary. The accumulation of 232Th occurs mainly in clayey fractions of the sediment. The distribution and accumulation of 40K is predominantly determined by the ratio of potassium contained in hydromica minerals. Significant 60Co activity was registered only in a few samples.
-
Energy Technology Data Exchange (ETDEWEB)
Mishunina, I B; Ledenev, A I; Khvesik, O V [Naukovo-Tekhnyichnij Tsentr z dezaktivatsyiyi ta kompleksnogo povodzhennya z radyioaktivnimi vyidkhodami, Zhovtyi Vodi (Ukraine)
1994-12-31
Preliminary estimation of soil water contamination as a result of radionuclide migration from burials is described. The studies necessary to make trustworthy prediction of soil water contamination are outlined.
-
Energy Technology Data Exchange (ETDEWEB)
Crossley, Jr., D. A. [Radiation Ecology Section, Health Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
1963-09-15
In early uses of radioactive tracers in ecological investigations of pests insect, dispersion and migration phenomena were studied with radioisotopes as markers for individual insects. A more recent development is the use of radioisotopes to evaluate insect-plant and predator-prey associations through estimates of food utilization. Biological elimination of radioisotopes, a nuisance in dispersion studies, is being utilized as a measure of feeding rates. In both field and laboratory experimentation, insects are allowed to reach steady-state concentrations of radioisotopes through feeding. Then the rate of intake is equal to the rate of elimination of the radioisotope: (rate of ingestion) = (steady-state amount) x (fractional rate of loss). Measurements of elimination rates (biological half-lives) permit the steady-state concentrations to be ttanslated into intake rate functions. Food consumption studies have been performed for single-insect-species populations and for multiple- species populations. In a single-species investigation, radiocaesium in a tagged field site was used to estimate the consumption of willow leaves by populations of the beetle Chrysomela knabi. Direct measurements of food consumption made in the laboratory showed good agreement with field estimates of feeding rates based on the radioisotope techniques. Biological half-lives differed for the larval stages and these had to be considered separately. Radioisotopes provided a means of separating overwintering adults from newly emerged ones, through the more rapid elimination of caesium from overwintering adults. In multiple-species work, the relationship between size of insect and elimination rate was used to derive an average biological half-life for radiocaesium elimination from herbivorous insects in a field site tagged with caesium-137. This average rate, used in conjunction with data on plant and insect biomasses and concentrations of radiocaesium, permitted an evaluation of plant consumption by an entire insect community. Similarly, the utilization of insects as food by predaceous arthropods was estimated from steady-state concentrations of radiocaesium in predators and prey, biomasses, and an average elimination rate. (author) [French] Dans les premiers travaux ecologiques sur les insectes nuisibles effectues a l'aide de radioindicateurs, les chercheurs ont etudie les phenomenes de dispersion et de migration en utilisant les radioisotopes pour le marquage d'individus. Plus recemment, ils s'en sont servis pour etudier les relations insecte-plante et predateur-proie, en procedant a des evaluations de l'utilisation des aliments. L'elimination biologique des radioisotopes, qui constitue un inconvenient dans les etudes sur la dispersion, est utilisee dans ce cas comme mesure des taux d'alimentation. Dans les experiences en plein champ ou en laboratoire, on attend que la concentration des radioisotopes ingeres par les insectes parvienne a l'equilibre. Le taux d'absorption des radiosotopes est alors egal a leur taux d'elimination: (taux d'ingestion) = (quantite a l'equilibre) x (taux de pertes fractionnaire). Les mesures des taux d'elimination (periode biologique) permettent de traduire les concentrations a l'equilibre en fonctions exprimant les taux d'ingestion. Les auteurs ont procede a des etudes sur la consommation d'aliments dans des populations composees d'une seule espece d'insectes et dans des populations composees de plusieurs especes. Dans une etude en plein champ sur une seule espece, ils ont procede au marquage par le radiocesium afin d'evaluer la consommation de feuilles de saule par des populations de chrysomeles (Chrysomela knabi). Les mesures directes de la consommation d'aliments faites en laboratoire ont bien concorde avec les evaluations des taux d'alimentation faites en plein champ au moyen des methodes radioisotopiques. Les periodes biologiques ont ete differentes pour les stades larvaires, qu'il a fallu etudier separement. Les radioisotopes om permis de distinguer les adultes ayant survecu a l'hiver de ceux qui venaient d'apparaltre; en effet, le cesium est elimine plus rapidement par les premiers. [Spanish] Las primeras aplicaciones de los indicadores radiactivos en los estudios ecologicos sobre las plagas de insectos y sobre los fenomenos de dispersion y migracion insectiles consistieron en marcar con radioisotopos a algunos insectos. Mas recientemente se han llegado a utilizar los radioisotopos para estudiar las relaciones insecto- planta y depredador-victima a traves del consumo de sustancias nutritivas. La eliminacion biologica de los radioisotopos, elemento perturbador en los estudios sobre la dispersion, sirve para medir los indices de alimentacion. Tanto en las campanas experimentales como en los estudios de laboratorio se logra una concentracion estacionaria de radioisotopos en los insectos por ingestion. El indice de ingestion de radioisotopos es entonces igual al de eliminacion; la formula aplicada es la siguiente (indice de ingestion) = (cantidad estacionaria) x (indice fraccional de perdida). La medida del indice de eliminacion (periodo biologico) permite determinar el indice de ingestion a partir de los datos relativos a la concentracion estacionaria. Se han estudiado el consumo de alimentos en poblaciones insectiles formadas por una sola especie y formadas por varias especies. En el estudio de una de las primeras, se utilizo el radiocesio aplicandolo en una zona determinada para calcular el consumo de hojas de sauce por poblaciones del escarabajo Chrysomela knabi. Las medicas directas del consumo de alimentos; realizadas en laboratorio, dieron resultados que coincidian con los obtenidos en las campanas experimentales emprendidas paia calcular los indices de alimentacion mediante el uso de radioisotopos. En la fase larval, el periodo biologico de los insectos es diferente, por lo que hubj de ser objeto de un estudio aparte. Los radioisotopos permitieron distinguir a los adultos que habian pasaco la hibernacion de los adultos nuevos, porque la eliminacion del cesio en los primeros era mas rapida. En los estudios sobre poblaciones formadas por varias especies, la relacion entre el tamano del insecto y el indice de eliminacion sirvio para calcular el periodo medio biologico para la eliminacion del radiocesio por insectos harbivoros en una zona tratada con {sup 137}Ce. Este periodo medio y los datos sobre las masas biologicas vegetales e insectiles y sobre las concentraciones de radiocesio han permitido calcular el consumo de vegetales de una poblacion entera de insectos. Del mismo modo, se ha podido calcular el consumo de insectos de los artropodos depredadores basandose en las concentraciones estacionarias de radiocesio en los depredadores y en las victimas, las masas biologicas y el indice medio de eliminacion. (author) [Russian] Pri bolee rannem ispol'zovanii radioaktivnykh indikatorov v ehkologicheskikh issledovaniyakh nasekomykh-vreditelej ikh rasseyaniya i migratsii izuchalis' pri pomoshchi radioizotopov, kotorymi markirovalis' otdel'nye nasekomye. V poslednee vremya poluchilo rasprostranenie ispol'zovanie radioizotopov dlya izucheniya biologicheskoj assotsiatsii nasekomykh i rastenij, a takkhe khishchnykh nasekomykh i ikh dobychi, iskhodya iz opredeleniya potrebleniya imi pishchi. Biologicheskoe vydelenie radioizotopov, kotoroe meshaet izucheniyu rasseyaniya nasekomykh, ispol'zuetsya v nastoyashchee vremya dlya izmereniya kolichestva potrebleniya pishchi. Kak v polevykh issledovaniyakh, tak i v laboratornykh ehksperimentakh nasekomym daetsya vozmozhnost' dostich' v protsesse pitaniya sostoyaniya ustojchivoj kontsentratsii radioizotopov. V ehtikh usloviyakh temp pogloshcheniya dannogo radioizotopa raven tempu ego vydeleniya: (temp pogloshcheniya) = (velichine ustojchivogo sostoyaniya) x (skorost' poteri); Izmereniya tempov vydeleniya (biologicheskogo poluraspada) pozvolyayut perevodit' sostoyaniya ustojchivoj kontsentratsii v funktsii tempov pogloshcheniya. Izuchenie potrebleniya pishchi bylo provedeno kak dlya populyatsij nasekomykh odnogo tol'ko vida, tak i dlya populyatsij smeshannogo tipa. Pri izuchenii nasekomykh odnogo vida na mechenom pole ispol'zovalsya radioaktivnyj tsezij dlya opredeleniya potrebleniya ivovykh list'ev populyatsiyami khuka Chrysomela knabl. Provedennye v laboratorii neposredstvennye izmereniya potrebleniya pishchi pokazali khoroshee sovpadenie s rezul'tatami izucheniya tempov pitaniya, poluchennymi na opytnom pole na osnovanii radioizotopnogo metoda. Odnako dlya lichinok biologicheskij period poluraspada okazalsya inym, tak chto ehti rezul'taty dolkhny rassmatrivat'sya razdel'no. S pomoshch'yu radioizotopov udalos' razdelit' perezimovavshikh vzroslykh osobej ot vnov' poyavivshikhsya na svet, blagodarya bolee bystromu vydeleniyu tseziya perezimovavshjmi vzroslymi osobyami. Pri rabote so smeshannymi populyatsiyami bylo ispol'zovano sootnoshenie mekhdu razmerom nasekomogo i tempami vydeleniya radioizotopov dlya opredeleniya srednego biologicheskogo perioda poluraspada pri vydelenii radioaktivnogo tseziya travoyadnymi nasekomymi, mechennymi tseziem-137. EHti srednie tempy sovmestno s dannymi o biomassakh rastenij i nasekomykh, a takkhe o kontsentratsiyakh radioaktivnogo tseziya pozvolili opredelit' razmery potrebleniya rastenij vsej populyatsiej nasekomykh. Analogichnym obrazom, kolichestvo nasekomykh, s{sup e}daemykh khishchnymi chlenistonogimi, bylo opredeleno na osnovanii sostoyaniya ustojchivoj kontsentratsii radioaktivnogo tseziya u khishchnikov i u ikh dobychi, ikh biomass i srednikh tempov vydeleniya. (author)
-
Energy Technology Data Exchange (ETDEWEB)
Gardonova, V.; Dulanska, S.; Bilohuscin, J. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra jadrovej chemie, 84215 Bratislava (Slovakia)
2013-04-16
Ecosystems, which include soil and sediments, contain not only natural radionuclides but also radionuclides from deposits, mainly {sup 137}Cs, {sup 90}Sr and {alpha}-emitting radionuclides such as {sup 239,240}Pu, {sup 238}Pu and {sup 241}Am, that originate from global fallout and nuclear facilities leaks worldwide. The goal of the work was optimization of separation and determination of {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu and {sup 241}Am in soil from Slovak Republic. The newest methods were applied for separation of selected radionuclides based on coprecipitation with oxalic salts and extraction chromatography using selective commercial sorbents. (authors)
-
Energy Technology Data Exchange (ETDEWEB)
Aglintsev, K K; Bochkarev, V V; Grablevskij, V N; Karavaev, F M
1960-06-15
}-istochniki prigotovlyayuts ya iz radionuklidov , vybrannykh takim obrazom, chtoby obespechit' diapazon ehnergij ot 0,018 mehv do 2,3 mehv. Kontrol'nye {beta}-istochniki prigotovlyayuts ya libo iz strontsiya-90 plyus ittrij-90, libo iz talliya-204, libo iz prometiya-147. EHti istochniki okhvatyvayut shirokij diapazon aktivnosti ot 20 do 10{sup 9} raspadov v minutu. Model'nye {gamma}-istochniki prigotovlyayuts ya libo iz radiya, libo iz kobal'ta-60, libo iz tseziya-137. diapazon aktivnostej ehtikh ehtalonov okhvatyvaet velichiny ot 10-{sup 11} do 5 grammov-ehkvivalento v radiya. Kontrol'nye u-istochniki prigotovlyayuts ya iz vysheukazanny kh radionuklidov. Aktivnosti okhvatyvayut ochen' shirokij diapazon, poskol'ku istochniki imeyut ves'ma razlichnuyu formu i razmery. Nakonets, model'nye istochniki nejtronov byvayut dvukh vidov: radija-{alpha}-berillij (soderzhashchij ot 1 do 1000 mg radiya) i plutonij-{alpha}-berilli j (soderzhashchij ot 0,01 do 15 grammov plutoniya). Istochniki radij-{alpha}-berilli j prigotovlyayutsya iz pressovannoj smesi RaBr{sub 2} i poroshkovogo berilliya s vesovym sootnosheniem Ra/Be = 1/6. Istochniki plutonij-a-berilli j obrazuyutsya iz splava (PuBe{sub 13}) ehtikh dvukh metallov. (author)