389 research outputs found
Влияние состава водной бронировки заряда из сплава тротила с гексогеном на выход и качество детонационного наноалмаза и алмазной шихты при детонационном синтезе
Приведены факторы детонационного синтеза, определяющие выход детонационных наноалмазов, алмазной шихты и их качество. Описано влияние такого важного фактора, как состав бронировки (оболочки) заряда взрывчатого вещества. Рассмотрены три различных варианта подрыва заряда взрывчатого вещества – газовый, водный, ледяной, их преимущества и недостатки. Показано влияние состава смесей водных растворов различных веществ (органических и неорганических) на результат детонационного синтеза.Наведено фактори детонаційного синтезу, що визначають вихід детонаційних наноалмазів, алмазної шихти та їх якість. Описано вплив такого важливого чинника, як склад бронювання (оболонки) заряду вибухової речовини. Розглянуто три різні варіанти підриву заряду вибухової речовини – газовий, водний, крижаний, їх переваги і недоліки. Показано вплив складу сумішей водних розчинів різних речовин (органічних і неорганічних) на результат детонаційного синтезу.This paper presents the factors of detonation synthesis, determining detonation nanodiamonds and the diamond blend yield and their quality We describe the effect of such an important factor as the composition of armor protection (shell) of the explosive charge. We consider three different ways of undermining an explosive charge – gas, water, ice, their advantages and disadvantages. We also shows the influence of the aqueous solutions composition of various mixtures of substances (organic and inorganic) on detonation synthesis result in details
Влияние состава бронировки стандартного заряда тротил–гексоген (50/50) на содержание примесей в детонационных наноалмазах
Рассмотрена возможность влияния на выход детонационных наноалмазов (ДНА),
алмазосодержащей шихты (АШ), содержание и состав несгораемых примесей в АШ и ДНА изменения
состава водной бронировки классического заряда тротил-гексоген (50/50). В качестве соединений,
влияющих на указанные параметры, использовали гидразин, уротропин, аммиак, мочевину, Трилон Б,
аминотетразол и борную кислоту.
Оптимальным по комплексу параметров оказался уротропин; в результате получен
максимальный выход ДНА (6,9%) и АШ (13,4%); близкий выход АШ и ДНА получен при использовании
в бронировке гидразина и мочевины. При использовании в бронировке борной кислоты существенно
сократилась номенклатура элементов примесей в АШ и ДНА при приемлемом выходе АШ (11,1%) и
ДНА (6,13%).Розглянуто можливість впливу на вихід детонаційних наноалмазів (ДНА), алмазовмістної
шихти (АШ), вміст і склад неспалених домішок в АШ і ДНА зміни складу водного бронювання класичного
заряду тротил-гексоген (50/50). В якості з'єднань, що впливають на зазначені параметри,
використовували гідразин, уротропін, аміак, сечовину, Трилон Б, амінотетразол і борну кислоту.
Оптимальним за комплексом параметрів виявився уротропін; в результаті отримано
максимальний вихід ДНА (6,9%) і АШ (13,4%); близький вихід АШ і ДНА отриманий при використанні
в бронюванні гідразину і сечовини. При використанні в бронюванні борної кислоти істотно
скоротилася номенклатура елементів домішок в АШ і ДНА при прийнятному виході АШ (11,1%) і ДНА
(6,13%).The paper considers the possibility to influence the yield of detonation nanodiamonds (DND), diamond
blend (DB), the content and composition of incombustible impurities in DB and DND by changing the aqueous
armoring composition of the classical charge TNT-RDX (50/50 As the compounds influencing the above
parameters were used: hydrazine, urotropin, ammonia, urea, Trilon B, aminotetrazole and boric acid.
Optimal for the complex of parameters was the use of urotropine, the maximum yield of DND (6.9%)
and DB (13.4%) was obtained, a close yield of DB and DND was obtained when hydrazine and urea were
used in the armoring. The use of boric acid in armor protection can significantly reduce the nomenclature of
impurity elements in the DB and DND with an acceptable yield of DB (11.1%) and DND (6.13%).
Using clean water for booking is not effective
Data driven Xpath generation
The XPath query language offers a standard for information extraction from HTML documents. Therefore, the DOM tree represen- tation is typically used, which models the hierarchical structure of the document. One of the key aspects of HTML is the separation of data and the structure that is used to represent it. A consequence thereof is that data extraction algorithms usually fail to identify data if the structure of a document is changed. In this paper, it is investigated how a set of tab- ular oriented XPath queries can be adapted in such a way it deals with modifications in the DOM tree of an HTML document. The basic idea is hereby that if data has already been extracted in the past, it could be used to reconstruct XPath queries that retrieve the data from a different DOM tree. Experimental results show the accuracy of our method
Exploring effects of remote ischemic preconditioning in a pig model of hypothermic circulatory arrest
Objectives. During aortic and cardiac surgery, risks for mortality and morbidity are inevitable. Surgical setups involving deep hypothermic circulatory arrest (DHCA) are effective to achieve organ protection against ischemic injury. The aim of this study was to identify humoural factors mediating additive protective effects of remote ischemic preconditioning (RIPC) in a porcine model of DHCA. Design. Twenty-two pigs were randomized into the RIPC group (n=11) and the control group (n=11). The RIPC group underwent four 5-minute hind limb ischemia-reperfusion cycles prior to cardiopulmonary bypass and DHCA. All animals underwent identical surgical procedures including 60min DHCA at 18 degrees C. Blood samples were collected from vena cava and sagittal sinus at several time points. After the 8-hour follow-up period, the brain, heart, and kidney tissue samples were collected for tissue analyses. Results. Serum levels of brain damage marker S100B recovered faster in the RIPC group, after 4hours of the arrest, (pPeer reviewe
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How predation and landscape fragmentation affect vole population dynamics
Background: Microtine species in Fennoscandia display a distinct north-south gradient from regular cycles to stable
populations. The gradient has often been attributed to changes in the interactions between microtines and their predators.
Although the spatial structure of the environment is known to influence predator-prey dynamics of a wide range of species,
it has scarcely been considered in relation to the Fennoscandian gradient. Furthermore, the length of microtine breeding
season also displays a north-south gradient. However, little consideration has been given to its role in shaping or generating
population cycles. Because these factors covary along the gradient it is difficult to distinguish their effects experimentally in
the field. The distinction is here attempted using realistic agent-based modelling.
Methodology/Principal Findings: By using a spatially explicit computer simulation model based on behavioural and
ecological data from the field vole (Microtus agrestis), we generated a number of repeated time series of vole densities
whose mean population size and amplitude were measured. Subsequently, these time series were subjected to statistical
autoregressive modelling, to investigate the effects on vole population dynamics of making predators more specialised, of
altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the
presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation and predator
assembly jointly determined cycle length and amplitude. Length of vole breeding season had little impact on the
oscillations.
Significance: There is good agreement between our results and the experimental work from Fennoscandia, but our results
allow distinction of causation that is hard to unravel in field experiments. We hope our results will help understand the
reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape
fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered in
future analyses of vole dynamics
Measurement of differential t(t)over-bar production cross sections in the full kinematic range using lepton plus jets events from proton-proton collisions at root s=13 TeV
Measurements of differential and double-differential cross sections of top-quark pair (t (t) over bar) production arc presented in the lepton + jets channels with a single electron or muon and jets in the final state. The analysis combines for the first time signatures of top quarks with low transverse momentum p(T), where the top-quark decay products can be identified as separated jets and isolated leptons, and with high p(T), where the decay products are collimated and overlap. The measurements arc based on proton-proton collision data at is - = 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The cross sections are presented at the parton and particle levels, where the latter minimizes extrapolations based on theoretical assumptions. Most of the measured differential cross sections are well described by standard model predictions with the exception of some double-differential distributions. The inclusive t (t) over bar production cross section is measured to be sigma(t (t) over bar) = 791 +/- 25 pb, which constitutes the most precise measurement in the lepton + jets channel to date.Peer reviewe
Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production
Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width—related to its lifetime—is an important parameter. One way to determine this quantity is to measure its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here we report evidence for such off-shell contributions to the production cross-section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at the 95% confidence level. The scenario with no off-shell contribution is excluded at a p-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as =3.2MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs
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